-- This SQL code deletes records from the 'customer1' table where the 'agent_code' column value matches any agent code from a subquery result.DELETEFROMcustomer1-- This line specifies the action of deleting records from the 'customer1' table.WHEREagent_code=ANY(-- This line specifies the ...
SQL DELETE Example To delete an employee with id 100 from the employee table, the sql delete query would be like,DELETE FROM employee WHERE id = 100; To delete all the rows from the employee table, the query would be like, DELETE FROM employee; ...
1. WITH ... SELECT ... 2. WITH ... UPDATE ... 3. WITH ... DELETE ... 1. 2. 3. ● 在子查询(包括派生表子查询)开始部分: 1.SELECT ... WHERE id IN (WITH ... SELECT ...) ... 2.SELECT * FROM (WITH ... SELECT ...) AS dt ... 1. 2. ● 紧跟在包含 SELECT 语句...
在进行数据查询时,有时我们需要从多个表中获取信息,这时嵌套查询(Subquery)便发挥了重要的作用。本文将深入探讨SQL Server中的嵌套查询,包括它的用法、优缺点以及代码示例。 何为嵌套查询? 嵌套查询(Subquery)是指在一个查询中嵌套了另一个查询。它可以存在于SELECT、INSERT、UPDATE和DELETE语句中。简单地说,嵌套查询...
-- SQL-2003 Standard subquery DELETE FROM Sales.SalesPersonQuotaHistory WHERE BusinessEntityID IN (SELECT BusinessEntityID FROM Sales.SalesPerson WHERE SalesYTD > 2500000.00); GO SQL Copier -- Transact-SQL extension DELETE FROM Sales.SalesPersonQuotaHistory FROM Sales.SalesPersonQuotaHistory AS spqh IN...
-- SQL-2003 Standard subqueryDELETEFROMSales.SalesPersonQuotaHistoryWHEREBusinessEntityIDIN(SELECTBusinessEntityIDFROMSales.SalesPersonWHERESalesYTD >2500000.00); GO SQL -- Transact-SQL extensionDELETEFROMSales.SalesPersonQuotaHistoryFROMSales.SalesPersonQuotaHistoryASspqhINNERJOINSales.SalesPersonASspONspqh.Busines...
开始我们拿sql到数据库查询平台查库执行计划,无奈这个平台有bug,delete语句无法查看,所以我们改成select,“应该”是一样。这个“应该”加了双引号,导致我们走了一点弯路。 EXPLAINSELECT*fromt_table_1wheretask_idin(selectidfromt_table_2whereuid=1)
可以使用具体的tableName来代替<left_subquery>与<right_subquery>。这与使用SELECT * FROM table子查询的方式相同。除非你的表是[Join](../operations/table_engines/join.md支持的JOIN类型:INNER JOIN、LEFT OUTER JOIN、RIGHT OUTER JOIN、FULL OUTER JOIN和CROSS JOIN。默认的OUTER关键字可以省略不写。
DROP USER user[,user]…; DROP USER li4 ; # 默认删除host为%的用户 DROP USER 'kangshifu'@'localhost'; #方式2:使用DELETE方式删除 DELETE FROM mysql.user WHERE Host=’hostname’ AND User=’username’; FLUSH PRIVILEGES; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10....
开始我们拿sql到数据库查询平台查库执行计划,无奈这个平台有bug,delete语句无法查看,所以我们改成select,“应该”是一样。这个“应该”加了双引号,导致我们走了一点弯路。 EXPLAIN SELECT * from t_table_1 where task_id in (select id from t_table_2 where uid = 1) ...