sql - Sql 选择联合计数

Question

我有一个存储过程，它返回带有一堆联合的行。我要做的是查看 select 语句是否不产生任何行，如果是，则执行另一个脚本。

这是我在存储过程中使用的当前 sql 选择。请让我知道如何实现这一目标。

SELECT  name AS [Name],  address1 AS Address1, address2 AS Address2, city AS City,  1 AS DeliveryTypeKey, email AS Email,  
  ( SELECT TOP 1   c_phone_number   
    FROM phone WITH (NOLOCK)  
    WHERE value = @value) AS Fax 
    FROM #Cities x    
 INNER JOIN prov p WITH (NOLOCK) ON x.ckey = p.pkey  
 UNION 
SELECT  name AS [Name], address1 AS Address1, address2 AS Address2, city AS City,  1 AS DeliveryTypeKey, email AS Email,  
  ( SELECT TOP 1 c_phone_number   
    FROM phone WITH (NOLOCK)  
    WHERE value = @value) AS Fax 
    FROM #Cities1 x    
    INNER JOIN prov1 p WITH (NOLOCK) ON x.ckey = p.pkey  
 UNION 
 SELECT  name AS [Name], address1 AS Address1, address2 AS Address2, city AS City,  1 AS DeliveryTypeKey, email AS Email,  
  ( SELECT TOP 1 c_phone_number   
    FROM phone WITH (NOLOCK)  
    WHERE value = @value) AS Fax 
 FROM #Cities2 x    
 INNER JOIN prov2 p WITH (NOLOCK) ON x.ckey = p.pkey 

Answer 1

使用 ROWCOUNT 函数检查是否返回了任何行：

DECLARE @table TABLE 
  ( 
     DATA INT 
  ) 

INSERT @table 
VALUES (0) 

SELECT * 
FROM   @table 
WHERE  DATA > 0 

IF @@ROWCOUNT = 0 
  SELECT 'run' 
ELSE 
  SELECT 'Don''t run'