1. 修改表字段的數(shù)據(jù)類型ALTER TABLE TabName MODIFY (ColName ColNewType);（*修改后的數(shù)據(jù)類型要兼容之前已經(jīng)存在的值）
2. 表增加一個(gè)字段 ALTER TABLE TabName ADD ColName ColType;
3. 同一個(gè)表內(nèi)copy表的字段ColName1值為另一個(gè)字段ColName2的值UPDATE TabName SET ColName1=ColName2;
4. 表刪除一個(gè)字段 ALTER TABLE TabName DROP ColName
5. 修改表的字段名ALTER TABLE TabName CHANGE ColOldName ColNewName ColType;
6. 查詢表中名稱不重復(fù)的數(shù)據(jù)：SELECT? COUNT(DISTINCT NAME) FROM inspection_item;
7. 查詢一個(gè)表的幾個(gè)字段復(fù)制到另外一個(gè)表的字段上：INSERT INTO inspection_standard2 (NAME,description) SELECT DISTINCT NAME,description FROM inspection_standard;
8. 查詢表的name字段重復(fù)的id：SELECT id FROM inspection_standard2 GROUP BY `name` HAVING COUNT(`name`)>1;
9. mysql把同一張表的一個(gè)字段內(nèi)的內(nèi)容復(fù)制到另一個(gè)字段里?update TabName set B=A;

10. 復(fù)制a表的完整字段結(jié)構(gòu)和索引到b表：CREATE TABLE b LIKE a;

11. CREATE TABLE inspection_info AS? SELECT * FROM inspection_agency;復(fù)制內(nèi)容

12. CREATE TABLE inspection_info AS? SELECT * FROM inspection_agency where 1 limit 0;只復(fù)制字段結(jié)構(gòu)

13. 刪除數(shù)據(jù)庫(kù)里面的外鍵約束：SET FOREIGN_KEY_CHECKS=0

14. 刪完表再添加上：SET FOREIGN_KEY_CHECKS=1

15. SELECT (CASE WHEN? shopid=-1 THEN? madminid ELSE shopid END)?? AS shangjiaID? FROM usercart當(dāng)某個(gè)字段的值為-1時(shí)，用另一個(gè)字段的值代替，組成一個(gè)新的組

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有關(guān)數(shù)據(jù)庫(kù)操作語(yǔ)句