当在 SQL Server 2008 中的表中找不到记录时，选择语句返回常量 [英] Select statement to return constant when no records found in table in SQL Server 2008

问题描述

我有一个包含数据的表，现在我需要在 select 语句中返回零，例如如果表中没有记录.我需要在存储过程中使用它.

I am have a table with data and now i need to return zero in select statement if there is no records in table for example. I need to use it in Stored Procedure.

-- If no records exists in below select statement
SELECT ID,Text,Date FROM tblData WHERE ID = 12

IF (@@ROWCOUNT = 0)
BEGIN
    SELECT -5 AS ID
END

输出:

ID  Text  Date


ID
-5

预期输出

ID
-5

推荐答案

SELECT (CASE WHEN Ta.ID IS NULL THEN TBL.ID 
ELSE Ta.ID END) AS ID,Ta.Text,Ta.Date
FROM (VALUES(-5)) AS TBL(ID)
LEFT JOIN
(
   SELECT ID,Text,Date FROM tblData WHERE ID = 12
)
AS Ta ON Ta.ID = Ta.ID

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