sql - 从 SQL 中的 Select 语句分配 INT 变量

Question

为什么在以下 SQL 语句中出现语法错误：

DECLARE @Count90Day int;

SET @Count90Day =  SELECT COUNT(*) FROM Employee WHERE DateAdd(day,30,StartDate) BETWEEN
DATEADD(day,-10,GETDATE()) AND DATEADD(day,10,GETDATE())  AND Active ='Y' 

我正在尝试将从我的 Select 语句返回的行数分配给变量 @Count90Day。

Answer 1

您需要围绕子查询的括号：

DECLARE @Count90Day int;

SET @Count90Day =  (SELECT COUNT(*)
                    FROM Employee
                    WHERE DateAdd(day,30,StartDate) BETWEEN DATEADD(day,-10,GETDATE()) AND 
                                                            DATEADD(day,10,GETDATE())  AND
                          Active ='Y'
                   );

您也可以在没有setas 的情况下编写它：

DECLARE @Count90Day int;

SELECT @Count90Day =  COUNT(*)
FROM Employee
WHERE DateAdd(day,30,StartDate) BETWEEN DATEADD(day,-10,GETDATE()) AND DATEADD(day,10,GETDATE()) AND
      Active ='Y';

Answer 2

您可以在 中分配它SELECT，如下所示：

DECLARE @Count90Day int;

SELECT @Count90Day = COUNT(*) 
FROM Employee 
WHERE DateAdd(day,30,StartDate) BETWEEN
DATEADD(day,-10,GETDATE()) AND DATEADD(day,10,GETDATE())  AND Active ='Y' 

Answer 3

这应该工作

DECLARE @Count90Day int;

SELECT @Count90Day = COUNT(*) FROM Employee WHERE DateAdd(day,30,StartDate) BETWEEN
DATEADD(day,-10,GETDATE()) AND DATEADD(day,10,GETDATE())  AND Active ='Y' 

Answer 4

您不会SELECT像那样分配 SQL 变量，您可以这样做：

SELECT @Count90Day = COUNT(*) 
FROM Employee WHERE DateAdd(day,30,StartDate) BETWEEN
DATEADD(day,-10,GETDATE()) AND DATEADD(day,10,GETDATE())  AND Active ='Y' 

Answer 5

您可以在语句中分配变量DECLARE，只需在请求周围使用圆括号。

DECLARE @Count90Day as int = (SELECT COUNT(*) 
                              FROM Employee 
                              WHERE DateAdd(day,30,StartDate) BETWEEN 
                                    DATEADD(day,-10,GETDATE()) AND
                                    DATEADD(day,10,GETDATE())  
                              AND Active ='Y')