Shulou(Shulou.com)06/01 Report--

Method 1:

When the publisher filter is null, how do I write SQL?

1 DECLARE @publishers VARCHAR(50);

2 SELECT * FROM dbo.Book WHERE Publishers=ISNULL(@publishers,Publishers)

Method 2:

declare @cinv varchar(50)

select * from inventory where 1=1 and (cInvName=@cinv or @cinv is null)

Method 3:

DECLARE @name VARCHAR(100),@page INT =1

SET @name='Zhang San'

DECLARE @sql VARCHAR(1000)

SET @sql='select * from myTable where 1=1'

IF @name IS NOT NULL

SET @sql=@sql+' and name='''+@name+'''--Character type Note the number of quotation marks

IF @page IS NOT NULL

SET @sql=@sql+' and page='+LTRIM(@page)--int type Note conversion to character type

--PRINT @sql

EXEC(@sql)

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