Question

为什么我在以下SQL中得到“关键字'IF'附近的语法不正确？”：

use AdventureWorks
CREATE FUNCTION Query2_Function(@DPT INT)
RETURNS TABLE
AS
RETURN
IF @DPT is not null
select edh.departmentid,d.name,count(*)as cnt 
    From HumanResources.Employee e
    inner join HumanResources.EmployeeDepartmentHistory edh on e.employeeID = edh.employeeid
    inner join humanresources.department d on edh.departmentid = d.departmentid
    where d.Name = @dpt
    group by edh.departmentid, d.name

Answer 1

在内联表值函数中不能有任何控制语句流。如果@dpt is null查询将返回空结果集

编辑：或者至少是否是正确的数据类型。您有@DPT INT并且正在与name列进行比较。这似乎注定要在执行时失败。

编辑2：

作为解决方案，您可以1）简单地删除IF @DPT is not null行和2）

将@DPT参数的类型从INT更改为varchar(100)，如果该函数应该按名称搜索部门，

或

将WHERE子句更改为以下内容：
```
where d.departmentid = @dpt
```
如果您打算按部门ID搜索。

Answer 2

试试这个

CREATE FUNCTION Query2_Function(@DPT INT)
RETURNS  @tbl TABLE 
   (
    departmentid    int  ,   
    [name]      varchar(100),
    cnt int          
   )
AS

begin

IF @DPT is not null
insert into @tbl (departmentid,name,cnt)
select edh.departmentid,d.name,count(*)as cnt 
    From HumanResources.Employee e
    inner join HumanResources.EmployeeDepartmentHistory edh on e.employeeID = edh.employeeid
    inner join humanresources.department d on edh.departmentid = d.departmentid
    where d.DepartmentID =@DPT 
    group by edh.departmentid, d.name
return  
 end

GO

关键字'IF'附近的语法不正确

2 个答案: