如何删除具有 2 列作为复合主键的多行

Question

例如，我们有以下查询在 Oracle 中有效，但是在 SQL 服务器中无效。 我们如何为 SQL 服务器重写它？

delete from cpi
where (countryid, year) in (('AD', 2010), ('AF', 2009), ('AG', 1992))

Answer 1

相比之下，它要笨重得多，但是您可以使用表值构造函数在EXISTS子句中创建元组列表并以这种方式匹配它，例如

DELETE FROM cpi
WHERE EXISTS 
      ( SELECT  1
        FROM (VALUES ('AD', 2010), ('AF', 2009), ('AG', 1992)) AS v (countryid, year)
        WHERE v.countryid = cpi.countryid
        AND v.year = cpi.year
      );

Answer 2

如果真的只有几对，只需：

 delete from cpi
 where (countryid = 'AD' and year = 2010) or (countryid = 'AF' and year = 2009) or (countryid = 'AG' and year = 1992)

或者，如果有更多，也许是这样的：

 delete from cpi
 where countryid + '|' + convert(varchar(4),year) in ('AD|2010','AF|2009','AG|1992')

Answer 3

您可以使用表值构造函数来表达这一点。 . . 在delete中：

delete from cpi
    from (values ('AD', 2010), ('AF', 2009), ('AG', 1992) ) v(countryid, year)
    where cpi.countryid = v.countryid and cpi.year = cpi.year;

不需要子查询。