sql常用語(yǔ)句舉例(更新版)
【正文】 me,last_name from custome16. Creat index：創(chuàng)建索引Creat index idx_custome_last_name on custome(last_name)17. Alter table:修改表加一個(gè)字段:Alter table custome add gender char(2)刪除一個(gè)字段：Alter table custome drop gender 改變字段名稱：Alter table custome change first_name f_name char(50)改變字段類型：Alter table custome modify first_name char(30)18. Primary key:主鍵,不能為空Alter table custome add primary key(sid)19. 外鍵：指向另一個(gè)表主鍵的字段Creat table users(u_id int,U_name char(20))Primary key(u_id)Foreign key(u_name) references custome(sid)20. Truncate table 表名:清除表中數(shù)據(jù)21. Insert into：向表中插入記錄Insert into stroe_information (store_name,sales,date) values (‘piny’,’$900’,’jan101999’)22. Update:更新記錄Update stroe_informationSet sales=$600Where store_name=’los angeles’And date=’jan081999’23. Delete:刪除記錄Delete from stroe_information where store_name=’los angeles’
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