Question

我具有以下oracle语法，该语法使我可以在IN语句（Source）中使用两列。不幸的是，该语句与MSSQL不兼容：

SELECT s.period, s.year, s.amount 
FROM salaries s
where (s.year, s.period) in (select year, period from periods)

我通过串联两个列找到了解决方案。但是，我想知道是否没有更专业的解决方案？

SELECT s.period, s.year, s.amount 
FROM salaries s
where (s.year + ' ' + s.period) in (select year + ' ' + period from periods)

Answer 1

您可以为此使用WHERE EXISTS。

SELECT s.period, s.year, s.amount 
FROM salaries s
where exists (
    SELECT *
    from periods
    where year = s.year and period = s.period
)

Answer 2

在MS SQL中，可以使用where存在方法，这种方法效率更高。

SELECT 
    s.period
    , s.year
    , s.amount 
FROM salaries s
where exists(
    select year, period from periods p where s.year = p.year and s.period = p.period
)

Answer 3

下面的代码将使用并行处理来消除[periods]表中不存在的记录：

SELECT DISTINCT s.[period]
      ,s.[year]
      ,s.amount 
FROM salaries s
CROSS APPLY
(SELECT * 
 FROM [periods]
 WHERE [year] = s.[year]
 AND [period] = s.[period]
)Res1

MSSQL-在子句中一次检查两列

3 个答案: