mysql根据条件执行sql

Posted 2023-03-26

参考技术A 在项目开发中，我们常常会用到根据不同条件，执行不同的sql,在mysql中可以用 IF(expr1,expr2,expr3) 来满足这个需求。下面我给大家一个示例：

示例1：sql比较复杂

SELECT

if(dom.PLAN_NO is null,

(ifnull( ( SELECT sum( DELIVERY_QTY ) FROM delivery_order_materiel WHERE 1=1 and PO_NO=pom.PO_NO and MATERIEL_CODE = pom.MATERIEL_CODE ), 0 )),

ifnull( ( SELECT sum( DELIVERY_QTY ) FROM delivery_order_materiel WHERE POM_PM_CODE = pom.PM_CODE AND PLAN_NO = dpm.PLAN_NO ), 0 )

)AS tempFiled

from tableName

where 1=1

示例2：

SELECT

if(dom.PLAN_NO=1,

( SELECT sum( DELIVERY_QTY ) FROM delivery_order_materiel WHERE 1=1 and PO_NO=pom.PO_NO and MATERIEL_CODE = pom.MATERIEL_CODE ),

( SELECT sum( DELIVERY_QTY ) FROM delivery_order WHERE 1=1 AND PLAN_NO = dpm.PLAN_NO )

)AS tempFiled

from tableName

where 1=1

sql 存储过程 - 根据条件执行不同的SQL语句

CREATE PROC [dbo].[GetUserByCondition]
        @username varchar(100),
        @orderfield  varchar(100)
     
         AS
                BEGIN
                    DECLARE @sqlfilter  VARCHAR(max)
                    SET @sqlfilter = 'select * from hrmresource where 1=1 '
                    IF(@username is not null)
                              SET @sqlfilter = @sqlfilter + '   and lastname like  ''%' +@username+ '%'' '
                    IF(@orderfield is not null)
                              SET @sqlfilter =  @sqlfilter +  '  order  by ' + @orderfield + ' desc' 
            
                            PRINT ( @sqlfilter)
                            EXEC (@sqlfilter)

                END
GO

exec GetUserByCondition '杨','workcode'