SQL Server 2008 R2:将别名与列值连接起来

问题描述

我有 Product 表，其中包含 QtyID、Qty 和 Year_ID 列.我还有一个表 tbl_Years 带有 ID 和 Year.

I have Product table with columns QtyID, Qty and Year_ID. I also have a table tbl_Years with ID and Year.

我有一个简单的 SELECT 语句，其中 SUM 计算 Qty:

I have a simple SELECT statement with SUM calculation of Qty:

SELECT 
    SUM(Qty) AS /*Sum_of_year_2016*/
FROM 
    Product p
INNER JOIN 
    tbl_Years ty ON p.Year_ID = ty.Year_ID
WHERE
    ty.Year_ID = 6;

我想为 SUM(Qty) 值定义别名 Sum_of_year_2016.

I want to define an alias name of Sum_of_year_2016 for the SUM(Qty) value.

注意:应从 tbl_Years 表中获取年份.

Note: the year should be fetched from the tbl_Years table.

我的尝试:

SELECT 
    SUM(Qty) AS 'Sum_of_year_' + ty.Year
FROM 
    Product p
INNER JOIN  
    tbl_Years ty ON p.Year_ID = ty.Year_ID
WHERE 
    ty.Year_ID = 6;

但我收到一个错误:

语法错误；'+' 附近的语法不正确.

Syntax error; incorrect syntax near '+'.

推荐答案

需要使用动态SQL获取自定义别名:

You need to use dynamic SQL to get custom alias:

DECLARE @year NVARCHAR(4) = (SELECT TOP 1 Year FROM  tbl_Years WHERE Year_id=6);

DECLARE @sql NVARCHAR(MAX) = 
'SELECT 
    SUM(Qty) AS ' + QUOTENAME('Sum_of_year_' + @year) +
' FROM Product p
INNER JOIN tbl_Years ty 
ON p.Year_ID = ty.Year_ID
Where ty.Year_ID = 6;';

EXEC sp_executesql @sql;