在SQL语句中构建动态where条件

Question

我想基于存储过程输入构建自定义Where条件,如果不是null,那么我将在语句中使用它们,否则我将不使用它们.

if @Vendor_Name is not null
    begin 

    set @where += 'Upper(vendors.VENDOR_NAME) LIKE "%"+ UPPER(@Vendor_Name) +"%"'

    end
    else if @Entity is not null
    begin
    set @where += 'AND headers.ORG_ID = @Entity'
    end
select * from table_name where @where

但是我得到了这个错误

An expression of non-boolean type specified in a context where a condition is expected, near 'set'.

Answer 1

用这个 ：

Declare @Where NVARCHAR(MAX) 

...... Create your Where

DECLARE @Command NVARCHAR(MAX) 
Set @Command = 'Select * From SEM.tblMeasureCatalog AS MC ' ;

If( @Where <> '' )
   Set @Comand = @Command + ' Where ' + @Where

Execute SP_ExecuteSQL  @Command

我测试了这个并且它有效

Answer 2

您不能像在此行中那样简单地将变量放在普通SQL中:

select * from table_name where @where;

您需要使用动态SQL.所以你可能有类似的东西:

DECLARE @SQL NVARCHAR(MAX) = 'SELECT * FROM Table_Name WHERE 1 = 1 ';
DECLARE @Params NVARCHAR(MAX) = '';

IF @Vendor_Name IS NOT NULL
    BEGIN
        SET @SQL += ' AND UPPER(vendors.VENDOR_NAME) LIKE ''%'' + UPPER(@VendorNameParam) + ''%''';
    END
ELSE IF @Entity IS NOT NULL
    BEGIN
        SET @SQL += ' AND headers.ORG_ID = @EntityParam';
    END;

EXECUTE SP_EXECUTESQL @SQL, N'@VendorNameParam VARCHAR(50), @EntityParam INT', 
                    @VendorNameParam = @Vendor_Name, @EntityParam = @Entity;

我假设您的实际问题更复杂,并且已经为此简化了它,但是如果使用所有谓词添加IF .. ELSE IF.. ELSE IF,那么您根本不需要动态SQL,您可以使用:

IF @Vendor_Name IS NOT NULL
    BEGIN
        SELECT  * 
        FROM    Table_Name
        WHERE   UPPER(vendors.VENDOR_NAME) LIKE '%' + UPPER(@Vendor_Name) + '%';
    END
ELSE IF @Entity IS NOT NULL
    BEGIN
        SELECT  * 
        FROM    Table_Name
        WHERE   headers.ORG_ID = @Entity;
    END