735 lines
12 KiB
Markdown
735 lines
12 KiB
Markdown
<!-- GFM-TOC -->
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* [??????????](#??????????)
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* [???????](#???????)
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* [???](#???)
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* [??????](#??????)
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* [????](#????)
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* [???](#???)
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* [?ݴ????](#?ݴ????)
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* [?¦Á?](#?¦Á?)
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* [??????](#??????)
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* [??????](#??????)
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* [?????](#?????)
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* [??????](#??????)
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<!-- GFM-TOC -->
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# ????
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????????????????¦Ä›¥???›¥???????????????????¦Ç?????????????????????
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??????????????????????????????????????????????????????????§Ö?????????
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SQL??Structured Query Language)????? SQL ?? ANSI ???????????????? ANSI SQL?????? DBMS ??????????????? PL/SQL??Transact-SQL ???
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# ???
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SQL ????????§³§Õ???????????????????????????????????????? DBMS ??????¨¢?
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**DISTINCT**
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????????????¦±??????????????§µ????????????§Ö????????????????
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```sql
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SELECT DISTINCT col1, col2
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FROM mytable;
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```
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**LIMIT**
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????????????????????????????????????????????§µ??? 0 ????????????????????????????
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????? 5 ?§Ö? SQL??
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```sql
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SELECT *
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FROM mytable
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LIMIT 5;
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```
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```sql
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SELECT *
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FROM mytable
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LIMIT 0, 5;
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```
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????? 3 \~ 5 ?§µ?
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```sql
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SELECT *
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FROM mytable
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LIMIT 2, 3;
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```
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**???**
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```sql
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# ???
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SELECT *
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FROM mytable -- ???
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/* ???1
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???2 */
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```
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# ????
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**ASC**??????????
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**DESC**??????
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?????????§ß???????
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```sql
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SELECT *
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FROM mytable
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ORDER BY col1 DESC, col2 ASC;
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```
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# ????
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????¨°??????????????????????????????§Û?????????????????????×Ï??????????????????????????????
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```sql
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SELECT *
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FROM mytable
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WHERE col IS NULL;
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```
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?¡À?????? WHERE ????????????
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| ?????? | ??? |
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| ------------ | ------------ |
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| = < > | ???? §³?? ???? |
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| <> != | ?????? |
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| <= !> | §³????? |
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| >= !< | ??????? |
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| BETWEEN | ?????????? |
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| IS NULL | ?NULL? |
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????????NULL ?? 0 ????????????????
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**AND OR** ??????????????????????????? AND?????????????????<3F>p????? AND ?? OR ????????? () ?????????????
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**IN** ??????????????????????????????? SELECT ????????????????????????
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**NOT** ????????????????????
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# ????
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??????????????????§µ?????????????¦±?
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- **%** ??? >=0 ????????????????? \*??
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- **\_** ??? ==1 ????????????????? \.??
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- **[ ]** ??????²®????????????????? ^ ?????????§Ù?
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??? Like ?????????????
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```sql
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SELECT *
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FROM mytable
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WHERE col LIKE '[^AB]%' -- ????AB????????????
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```
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?????????????????¦Ë????????????????
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# ???????
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?????????????????????????????????????????????????????????????????????????????????????????????????
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???????????????? **AS** ????????????????????????????????????
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```sql
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SELECT col1*col2 AS alias
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FROM mytable
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```
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**Concat()** ??????????????¦±?????????????????????????§á?????????????????§»???????????? **TRIM()** ?????????¦Â???
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```sql
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SELECT Concat(TRIM(col1), ' (', TRIM(col2), ')')
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FROM mytable
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```
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# ????
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???? DBMS ???????????????????????????
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## ???????
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| ???? | ??? |
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| ------------ | ------------ |
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| LEFT() RIGHT() | ????????????? |
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| LOWER() UPPER() | ????§³§Õ?????§Õ |
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| LTRIM() RTIM() | ??????????????? |
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| LENGTH() | ???? |
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| SUNDEX() | ????????? |
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???§µ?**SOUNDEX()** ????????????????????????????????????????????????????????????????????
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```sql
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SELECT *
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FROM mytable
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WHERE SOUNDEX(col1) = SOUNDEX('apple')
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```
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## ??????????
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????????YYYY-MM-DD
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???????HH:MM:SS
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|?? ?? | ? ??|
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| --- | --- |
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| AddDate() | ??????????????????|
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| AddTime() | ?????????????????|
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| CurDate() | ?????????? |
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| CurTime() | ????????? |
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|Date() |???????????????????|
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|DateDiff() |???????????????|
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|Date_Add() |?????????????????|
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|Date_Format() |??????????????????????|
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|Day()| ????????????????????|
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|DayOfWeek() |?????????????????????????|
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|Hour() |???????????§³?????|
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|Minute() |?????????????????|
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|Month() |?????????????¡¤????|
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|Now() |??????????????|
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|Second() |???????????????|
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|Time() |????????????????????|
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|Year() |??????????????????|
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```sql
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mysql> SELECT NOW();
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-> '2017-06-28 14:01:52'
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```
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## ???????
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| ???? | ??? |
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| --- | --- |
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| SIN() | ???? |
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|COS() | ???? |
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| TAN() | ???? |
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| ABS() | ????? |
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| SQRT() | ?????|
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| MOD() | ????|
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| EXP() | ???|
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| PI() | ?????|
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|RAND() | ?????|
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## ????
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|?? ?? |? ??|
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| --- | --- |
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|AVG() |??????§Ö?????|
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|COUNT()| ??????§Ö?????|
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|MAX()| ??????§Ö?????|
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|MIN()| ??????§Ö???§³?|
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|SUM() |???????????|
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AVG() ????? NULL ?§³?
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DISTINCT ??????????????????
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```sql
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SELECT AVG(DISTINCT col1) AS avg_col
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FROM mytable
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```
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# ????
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?????????????????????????§³?
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????????????????????????§Õ???????????????????????
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?? col ????????????
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```sql
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SELECT col, COUNT(*) AS num
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FROM mytable
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GROUP BY col;
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```
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WHERE ?????§µ?HAVING ??????ï…?§Û?????????????????
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```sql
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SELECT col, COUNT(*) AS num
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FROM mytable
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WHERE col > 2
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GROUP BY col
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HAVING COUNT(*) >= 2;
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```
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GROUP BY ???????????????¦²??? ORDER BY ??????????????????????
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```sql
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SELECT col, COUNT(*) AS num
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FROM mytable
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GROUP BY col
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ORDER BY num;
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```
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????ÕÇ??
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1. GROUP BY ???????? WHERE ??????ORDER BY ???????
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2. ????????????????SELECT ????§Ö????§Ø??????? GROUP BY ????§Ú?????
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3. NULL ???§Ý????????ï”
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4. ????? SQL ??????? GROUP BY ?§à??§á??????????????
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# ????
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????????????????§³?
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???????????????? WHRER ?????????????
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```
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SELECT *
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FROM mytable1
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WHERE col1 IN (SELECT col2
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FROM mytable2);
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```
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?????????????????????????????????????????????????????????¦²?
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```sql
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SELECT cust_name, (SELECT COUNT(*)
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FROM Orders
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WHERE Orders.cust_id = Customers.cust_id)
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AS orders_num
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FROM Customers
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ORDER BY cust_name;
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```
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# ????
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??????????????????? JOIN ???????????????????? ON??
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????????<3F>I?????????????????§¹?????????
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?????? AS ??????????????¦Ê???????????????????????????? SQL ???????????????
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## ??????
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??????????????????? INNER JOIN ??????
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```
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select a, b, c
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from A inner join B
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on A.key = B.key
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```
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??????????? INNER JOIN????????????????? WHERE ?§ß???????????????????????????????????
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```
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select a, b, c
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from A, B
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where A.key = B.key
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```
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?????????????????¡¤???????????
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## ??????
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??????????????????????????????????????????
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??????????????????????????????????????? Jim ????????????????????????
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**?????·Ú**
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```
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select name
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from employee
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where department = (
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select department
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from employee
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where name = "Jim");
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```
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**??????·Ú**
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```
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select name
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from employee as e1, employee as e2
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where e1.department = e2.department
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and e1.name = "Jim";
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```
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??????????????§¹????
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## ???????
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????????????????????????????????????????§á????§Ø????
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?????????????????????????????????§µ?????????????????????????§µ???????????????????
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```
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select *
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from employee natural join department;
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```
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## ??????
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?????????????§Û???????§»?§³???????????????????????????????????????????????????????§³?
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???????§Û???????????????????§Ø???????????
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```
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select Customers.cust_id, Orders.order_num
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from Customers left outer join Orders
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on Customers.cust_id = Orders.curt_id
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```
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??????????????????????????????
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```
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select Customers.cust_id,
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COUNT(Orders.order_num) as num_ord
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from Customers left outer join Orders
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on Customers.cust_id = Orders.curt_id
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group by Customers.cust_id
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```
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# ?????
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??? **UNION** ??????????????????????????????????§³?????????????????
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???????????§µ???????????????§µ???? UNION ALL ??
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????????? ORDER BY ??????????¦Ë?????????
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```sql
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SELECT col
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FROM mytable
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WHERE col = 1
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UNION
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SELECT col
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FROM mytable
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WHERE col =2;
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```
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# ????
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**???????**
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```sql
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INSERT INTO mytable(col1, col2)
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VALUES(val1, val2);
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```
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**?????????????????**
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```sql
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INSERT INTO mytable1(col1, col2)
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SELECT col1, col2
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FROM mytable2;
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```
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**????????????????????¡À?**
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```sql
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CREATE TABLE newtable AS
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SELECT * FROM mytable;
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```
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# ????
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```sql
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UPDATE mytable
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SET col = val
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WHERE id = 1;
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```
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# ???
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```sql
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DELETE FROM mytable
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WHERE id = 1;
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```
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**TRUNCATE TABLE** ?????????????????????§³?
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????????????????????? WHERE ????????????????????????????????? SELECT ?????§Ó????????????????
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# ??????
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```sql
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CREATE TABLE mytable (
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id INT NOT NULL AUTO_INCREMENT,
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col1 INT NOT NULL DEFAULT 1,
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col2 VARCHAR(45) NULL,
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col3 DATE NULL,
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PRIMARY KEY (`id`));
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```
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# ????
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**?????**
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```sql
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ALTER TABLE mytable
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ADD col CHAR(20);
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```
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**?????**
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```sql
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ALTER TABLE mytable
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DROP COLUMN col;
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```
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**?????**
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```sql
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DROP TABLE mytable;
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```
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# ???
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?????????????????????????????????????????????????????????????????????????
|
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???????????????
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1. ?????? SQL ?????????¿y???????
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||
2. ???????????????????
|
||
3. ???????????????????????????????????
|
||
4. ????????????????
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|
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```sql
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CREATE VIEW myview AS
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SELECT Concat(col1, col2) AS concat_col, col3*col4 AS count_col
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FROM mytable
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WHERE col5 = val;
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```
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# ?ݴ????
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|
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?ݴ????????????????? SQL ????????????
|
||
|
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**???ݴ???????**
|
||
|
||
1. ???????????›¥?????§µ???????????????????
|
||
2. ??????????
|
||
3. ?????????????????§Ü????????
|
||
|
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**?????ݴ????**
|
||
|
||
???????§Õ????›¥??????????????????????????????? ; ????????????›¥???????????????????????????????????????????????????
|
||
|
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???? in??out ?? inout ?????????
|
||
|
||
???????????????? select into ???
|
||
|
||
?????????????????????????????????
|
||
|
||
```sql
|
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delimiter //
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|
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create procedure myprocedure( out ret int )
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begin
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declare y int;
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select sum(col1)
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from mytable
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into y;
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select y*y into ret;
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||
end //
|
||
delimiter ;
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||
```
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```sql
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call myprocedure(@ret);
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select @ret;
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```
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|
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# ?¦Á?
|
||
|
||
??›¥??????????¦Á??????????????????????????
|
||
|
||
?¦Á??????????????????????????????????§Ö??????§ß????????????
|
||
|
||
**????¦Á????????Ñs**
|
||
|
||
1. ?????¦Á????????????????????????
|
||
2. ???¦Á?
|
||
3. ????????
|
||
4. ????¦Á?
|
||
|
||
```sql
|
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delimiter //
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create procedure myprocedure(out ret int)
|
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begin
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declare done boolean default 0;
|
||
|
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declare mycursor cursor for
|
||
select col1 from mytable;
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# ?????????continue handler???? sqlstate '02000' ??????????????????? set done = 1
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declare continue handler for sqlstate '02000' set done = 1;
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|
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open mycursor;
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repeat
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fetch mycursor into ret;
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select ret;
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until done end repeat;
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close mycursor;
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end //
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delimiter ;
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```
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|
||
# ??????
|
||
|
||
?????????????????????????????????§µ?DELETE??INSERT??UPDATE
|
||
|
||
???????????????????????????????????§µ????????? BEFORE ??????????????? AFTER ??????BEFORE ??????????????????
|
||
|
||
INSERT ???????????????? NEW ???????
|
||
|
||
```sql
|
||
CREATE TRIGGER mytrigger AFTER INSERT ON mytable
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||
FOR EACH ROW SELECT NEW.col;
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||
```
|
||
|
||
DELETE ???????????????? OLD ???????????????????
|
||
|
||
UPDATE ???????????????? NEW ???????? OLD ??????????? NEW ????????????? OLD ????????
|
||
|
||
???????????????????????????????????????????§³?
|
||
|
||
MySQL ?????????????????? CALL ??? ?????????????ݴ?????
|
||
|
||
# ??????
|
||
|
||
**????????**
|
||
|
||
1. ????transaction?????? SQL ???
|
||
2. ?????rollback?????????? SQL ????????
|
||
3. ????commit?????¦Ä?›¥?? SQL ?????§Õ????????
|
||
4. ??????savepoint????????????????????¦Ë????placeholder?????????????????????????????????????????
|
||
|
||
??????? SELECT ??????? SELECT ????????‰Ù???????? CRETE ?? DROP ???
|
||
|
||
MySQL ?????????????????????????????????????????¦±??????? START TRANSACTION ??????????????????? COMMIT ?? ROLLBACK ?????§Ü??????????????????????????
|
||
|
||
??????? autocommit ? 0 ????????????????? autocommit ??????? 1 ???????autocommit ???????????????????????????????
|
||
|
||
???????????????ROLLBACK ?????? START TRANSACTION ????????????????????????? ROLLBACK ??????????????????????????
|
||
|
||
```sql
|
||
START TRANSACTION
|
||
// ...
|
||
SAVEPOINT delete1
|
||
// ...
|
||
ROLLBACK TO delete1
|
||
// ...
|
||
COMMIT
|
||
```
|
||
|
||
# ?????
|
||
|
||
**????????**
|
||
|
||
1. ???????????????????
|
||
2. ??????????????????????????
|
||
3. §µ??????????¦Á?????????????????î•
|
||
|
||
?????????????????§µ?????????????????
|
||
|
||
```sql
|
||
CREATE TABLE mytable
|
||
(col VARCHAR(10) CHARACTER SET latin COLLATE latin1_general_ci )
|
||
DEFAULT CHARACTER SET hebrew COLLATE hebrew_general_ci;
|
||
```
|
||
|
||
?????????????????§µ???
|
||
|
||
```sql
|
||
SELECT *
|
||
FROM mytable
|
||
ORDER BY col COLLATE latin1_general_ci;
|
||
```
|
||
|
||
# ??????
|
||
|
||
MySQL ?????????????? mysql ?????????§³?
|
||
|
||
```sql
|
||
USE mysql;
|
||
SELECT user FROM user;
|
||
```
|
||
|
||
**???????**
|
||
|
||
```sql
|
||
CREATE USER myuser IDENTIFIED BY 'mypassword';
|
||
```
|
||
|
||
??????????????¦Ê?????
|
||
|
||
**????????**
|
||
|
||
```sql
|
||
RENAME myuser TO newuser;
|
||
```
|
||
|
||
**??????**
|
||
|
||
```sql
|
||
DROP USER myuser;
|
||
```
|
||
|
||
**?????**
|
||
|
||
```sql
|
||
SHOW GRANTS FOR myuser;
|
||
```
|
||
|
||
|
||
????? username@host ????????ÈÉusername@% ?????????????????
|
||
|
||
**???????**
|
||
|
||
```sql
|
||
GRANT SELECT, INSERT ON mydatabase.* TO myuser;
|
||
```
|
||
|
||
**??????**
|
||
|
||
```sql
|
||
REVOKE SELECT, INSERT ON mydatabase.* FROM myuser;
|
||
```
|
||
|
||
GRANT ?? REVOKE ??????????????????????
|
||
|
||
- ??????????????? GRANT ALL?? REVOKE ALL??
|
||
- ???????????? ON database.\*??
|
||
- ????????? ON database.table??
|
||
- ??????§µ?
|
||
- ?????ݴ?????
|
||
|
||
**????????**
|
||
|
||
??????? Password() ????
|
||
|
||
```sql
|
||
SET PASSWROD FOR myuser = Password('newpassword');
|
||
```
|
||
|