Question

我从此代码中得到一个错误

DECLARE @existingEmail AS INT

SET NOCOUNT ON;

@existingEmail = COUNT(*) AS total FROM table WHERE email = @email;

INSERT INTO table2 (email)
VALUES (CASE WHEN @existingEmail IS 1 THEN 'Yes' ELSE 'No' END);

那是我得到的错误

第15行，状态1，过程sp_counts，第21行，消息[第7行开始]
“ @existingEmail”附近的语法不正确。

Answer 1

从性能的角度来看，使用COUNT来检查是否存在并不是最好的主意：

INSERT INTO table2 (email)
SELECT CASE WHEN EXISTS (SELECT 1 FROM table WHERE email = @email) THEN 'Yes' 
       ELSE 'No' END

Answer 2

代替此：

@existingEmail = COUNT(*) as total from table where email = @email;

您需要执行以下操作：

SELECT @existingEmail = COUNT(*) as total from table where email = @email;

或者这个：

SET @existingEmail = (SELECT COUNT(*) as total from table where email = @email);

Answer 3

在您试图设置变量@existingEmail的那一行中，您缺少关键字set。如果将该行更新为以下内容，则应该可以解决该错误。

set @existingEmail = (SELECT COUNT(*) from table where email = @email);

卡在SQL Server过程代码上

3 个答案: