Question

我创建了以下存储过程，在创建新员工时将调用该过程。只要员工在Employee表中不存在，插入就应该成功。

为了检查这一点，我决定检查FirstName，LastName和DateOfBirth。如果一行包含所有这些列的3路匹配，则插入失败。

我所看到的是，If语句将我的AND视为OR。如果发生一次匹配，则插入失败。

经过一番搜索，我无法看到我的If结构出了什么问题。任何帮助将不胜感激。

            Create Procedure CreateEmployee
            (
            @Role_ID Int,
            @FirstName Varchar(50),
            @LastName Varchar(50),
            @DateOfBirth Varchar(50),
            @Active Bit
            )
            As
            Begin

            If Not Exists (Select FirstName From Employee Where FirstName = @FirstName)
                AND Not Exists (Select LastName From Employee Where LastName = @LastName)
                AND Not Exists (Select DateOfBirth From Employee Where DateOfBirth = @DateOfBirth)

                Begin
                Insert Into Employee (Role_ID, FirstName, LastName, DateOfBirth, Active)
                Values (@Role_ID, @FirstName, @LastName, @DateOfBirth, @Active)
                End

            Else
                Begin
                Select 'User already exists!'
                End

            End

Answer 1

为什么你不只是为你的支票运行1个查询？

If Not Exists (Select 1 From Employee 
               Where FirstName = @FirstName 
                     and LastName = @LastName 
                     and DateOfBirth = @DateOfBirth)
    begin
        ...

Answer 2

这是（sql server的@@rowcount）的另一种方式：使用Where not exists。 Similar Sql Fiddle Demo

Insert Into Employee (Role_ID, FirstName, LastName, DateOfBirth, Active)
Select @Role_ID, @FirstName, @LastName, @DateOfBirth, @Active
Where not exists (
  select 1 from Employee where FirstName = @FirstName 
                         and LastName = @LastName 
                         and DateOfBirth = @DateOfBirth
)

If @@rowcount=0 select 'User already exists!'

SQL - 如果声明看似忽略'AND'

2 个答案: