Question

我有以下四个参数的存储过程。

存储过程spTest：

CREATE PROCEDURE spTest
    @Name varchar(20) = '',
    @Address varchar(100) = '',
    @City varchar(50) = '',
    @Pin varchar(50) = ''
AS
    DECLARE @DynamicWhere varchar(max)
    DECLARE @Query varchar(max)

    /* Here I want to prepare a dynamic where clause for all possibilities */
    SET @Query = 'SELECT * FROM Test_Table '+ @DynamicWhere +'';

    EXECUTE(@Query);
GO

好吧，我正在准备这样：

IF @Name = '' AND @Address = '' AND @City = '' AND @Pin = '' 
BEGIN
     SET @DynamicWhere = '';
END
ELSE IF @Name != '' AND @Address = '' AND @City = '' AND @Pin = '' 
BEGIN
     SET @DynamicWhere = 'Name ='''+@Name+'''';
END
ELSE IF @Name != '' AND @Address != '' AND @City = '' AND @Pin = '' 
BEGIN
     SET @DynamicWhere = 'Name ='''+@Name+''' AND Address ='''+@Address+'''';
END
......
......
Many possibilities

这是正确的方法 OR 有没有更好的方法来准备动态WHERE条款？

Answer 1

它被称为catch-all查询，它基本上是这样的：

CREATE PROCEDURE spTest
    @Name varchar(20) = '',
    @Address varchar(100) = '',
    @City varchar(50) = '',
    @Pin varchar(50) = ''
AS
    SELECT * 
    FROM Test_Table 
    WHERE (@Name = '' OR Name = @Name)
    AND (@Address = '' OR Address = @Address)
    AND (@City = '' OR City = @City)
    AND (@Pin = '' OR Pin = @Pin);
GO

您也可以阅读this article about catch all queries

Answer 2

在这种情况下你也可以使用ISNULL和NULLIF：
下面的代码应该工作：

CREATE PROCEDURE spTest
    @Name varchar(20) = '',
    @Address varchar(100) = '',
    @City varchar(50) = '',
    @Pin varchar(50) = ''
AS
    SET @Name=NULLIF(@Name,'')
    SET @Address=NULLIF(@Address,'')
    SET @City=NULLIF(@City,'')
    SET @Pin=NULLIF(@Pin,'')

    SELECT * 
    FROM Test_Table 
    WHERE Name = ISNULL(@Name,Name)
    AND Address = ISNULL(@Address,Address)
    AND City = ISNULL(@City,City)
    AND Pin = ISNULL(@Pin,Pin)

GO

Answer 3

我更新了@Zohar的答案。定义空白是坏习惯，理想情况下定义为null，然后使用空白。所以查询将是

CREATE PROCEDURE spTest
    @Name varchar(20) = null,
    @Address varchar(100) = null,
    @City varchar(50) = null,
    @Pin varchar(50) = null
AS
    SELECT * 
    FROM Test_Table 
    WHERE (Name = ISNULL(@Name,'') )
    AND (Address = ISNULL(@Address,''))
    AND (City = ISNULL(@City,''))
    AND (Pin = ISNULL(@Pin,''));
GO

即使我喜欢@Biswa的答案，因为它使用当前版本的sql server，但是Sqlserver 2008R2没有这个功能。

SQL Server 2008 R2：准备动态WHERE子句

3 个答案: