SQL2

1、移去空格

replace(@CertigierEmpId,' ','')

2、值对应转换显示

SELECT (case FlowStatus WHEN 1 then 4 WHEN 2 then 3 END ) AS FlowStatus FROM dbo.FlowExpense

3、表中插入一个字段

ALTER TABLE [dbo].[HR_ShiftConfig]
ADD Duration DECIMAL(18,1) NULL

4.exists 比left join性能更优

SELECT * FROM dbo.OKR_ObjectEvaluateItem AS items
WHERE CheckEmpId =0 and
EXISTS(
SELECT 1 FROM dbo.OKR_ObjectEvaluate 
WHERE EvaluateEndTime <GETDATE() AND ObjectStatus =3 AND items.MainID = ID)　

5.像如下这样查值，如果没有找到，或输入-1

declare @FlowCheckStatus int 
set @FlowCheckStatus = -1
select @FlowCheckStatus = FlowCheckStatus from GB_FloCheckStepInforWip where id =-1
print @FlowCheckStatus

6.已知表名为字符串，查询表中数据。注意绿色处，带出值得方法必须重设置一个字符变量

declare @TableName nvarchar(200),@FlowID INT ,@FlowNo nvarchar(100),@FlowInitiateEmpID int
set @TableName = 'HR_FloLeaveOver'
SET @FlowID = 130
--exec ('select * from ' + @TableName + ' where ID = ' + ''+@FlowID+ '')
--带出值
declare @FlowIDStr nvarchar(200)
set @FlowIDStr = cast(@FlowID as nvarchar(200))
declare @SqlStr nvarchar(1000)
set @SqlStr = N'select top 1 @a = FlowNo,@b= FlowInitiateEmpID from '+ @TableName +' where ID = '+ @FlowIDStr
exec sp_executesql @SqlStr,N'@a nvarchar(100) output,@b int output',@FlowNo output,@FlowInitiateEmpID output

print @FlowNo
print @FlowInitiateEmpID

--用=‘’判断进不去的

if @FlowNo is null or @FlowInitiateEmpID is null
begin
print '为空！'
end