Question

我的存储过程（SQL Server）中有以下查询：

SELECT 
    ea.attendanceid,
    ea.employeeid,

    FROM employee_attendance ea

    WHERE 
    ea.masterentity = @masterentity
    AND ea.employeeid = @employeeid

    -- here I need to know what value @type is and then create my conditionals
    AND (ISNULL(@type,'') = '' OR 
        .......

我的参数@type有不同的字符串值：

IL =内部午餐
EL =外部午餐
L =所有午餐
N =仅正常
R = Especial

根据值，我必须过滤的列：

If `@type='IL'` then I have to filter: `AND ea.lunchtype = 'C'`
If `@type='EL'` then I have to filter: `AND ea.lunchtype = 'CI'`
If `@type='L'` then I have to filter: `AND ea.islunch = 1`
If `@type='N'` then I have to filter: `AND ea.islunch = 0`
If `@type='R'` then I have to filter: `AND (ea.ismanual = 1 AND ea.lunchtype = 'K')`

关于如何实现这一目标的任何线索？

Answer 1

您需要以类似的方式转换为SQL

AND ( 
ISNULL(@type, ' ') = ' '
OR ( @type='IL' AND ea.lunchtype = 'C' )
OR ( @type='EL' AND ea.lunchtype = 'CI' )
OR (@type='L' AND ea.islunch = 1   )
OR (@type='N' AND ea.islunch = 0    )
OR (@type='R'  AND (ea.ismanual = 1 AND ea.lunchtype = 'K')
)
)

Answer 2

使用CASE声明。

CASE可用于允许有效表达式的任何语句或子句。例如，您可以在SELECT，UPDATE，DELETE和SET等语句中使用CASE，也可以在select_list，IN， WHERE ，ORDER BY和HAVING等子句中使用CASE。

MSDN CASE (Transact-SQL)

请参阅本页上有关如何使用的示例。

Where子句与存储过程中的条件

2 个答案: