SQL Case表达式是一种条件表达式,用于在SQL查询中根据不同的条件返回不同的结果。它可以根据给定的条件进行逻辑判断,并根据判断结果返回相应的值或执行相应的操作。 Case表达式通常有两种形式:...
It is also possible to stack multiple conditions inside a singleCASEclause. Syntax SELECTcolumn1, column2, ...CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededENDASalias_nameFROMtable_name; We can add as manyWHEN ... THENconditions as requi...
代码语言:txt 复制 SELECT employee_id, CASE WHEN gender = 'M' THEN '男' WHEN gender = 'F' THEN '女' ELSE '未知' END AS gender_desc FROM employees; 常见问题及解决方法: 问题:在使用CASE语句时,发现返回的结果不符合预期。 原因: 条件判断错误或不完整。 数据类型不匹配。 解决方法: ...
Silver（银卡）或Bronze（铜卡）。SELECTcustomer_name,CASEWHENtotal_purchases>=10000THEN'Gold'WHENtotal...
SQL基础学习笔记 一、建库建表 1、检查数据库名是否存在 如果需要创建数据库,可能会出现数据库名字重名的现象,我们可以使用如下代码查询数据库名是否存在,存在则删除此数据库。 --删除数据库 if exists(select * from sys.databases where name = 
6、通过sqlId+dialect模式,可针对特定数据库写sql,sqltoy根据数据库类型获取实际执行sql,顺序为: dialect_sqlId->sqlId_dialect->sqlId,如数据库为mysql,调用sqlId:sqltoy_showcase,则实际执行:sqltoy_showcase_mysql <sql id="sqltoy_showcase"> <value> <![CDATA[ select * from sqltoy_user_log t where...
(2))) + 1; --Special case: Dec 29-31 may belong to the next year IF ((DATEPART(mm, @DATE) = 12) AND ((DATEPART(dd, @DATE) - DATEPART(dw, @DATE)) >= 28)) SET @ISOweek = 1; RETURN (@ISOweek); END; GO SET DATEFIRST 1; SELECT dbo.ISOweek(CONVERT(DATETIME, '12/26/...
一个复杂的sql语句 IF((SELECTCOUNT(*)fromfn_lis_redois('MS_Description','SCHEMA',N'dbo','...
In this case, the script assembles the following query: SQL SELECT*FROMOrdersTableWHEREShipCity ='Redmond';droptableOrdersTable--' The semicolon (;) denotes the end of one query and the start of another. The double hyphen (--) indicates that the rest of the current line is a comment ...
/// <summary> /// Lookup name inside the resources file for the select asterisk rule name /// </summary> public const string AvoidWaitForDelay_RuleName = "AvoidWaitForDelay_RuleName"; /// <summary> /// Lookup ID inside the resources file for the select asterisk description //...