select COUNT(*) from (select 1 id union select null union select 2) as a;
select COUNT(id) from (select 1 id union select null union select 2) as a;
两者有什么区别吗。结果不一样。
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MSSQL2008R count
select COUNT(*) from (select 1 id union select null union select 2) as a; select COUNT(id) from (select 1 id union select null union select 2) as a; 两者有什么区别吗。结果不一样。