SELECT isnull(id,'a') as id ,isnull(SUM(b),0) as b FROM tb WHERE tb.id='a'
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SELECT isnull(id,'a') as id ,SUM(isnull(b,0)) as b FROM tb WHERE tb.id='a'
SELECT 'a',SUM(b) FROM tb WHERE tb.id='a'
当tb.id='a'不存在时,想得出如下的结果:
a 0
怎么实现?
谢谢。
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当tb.id='a'不存在时,想得出如下的结果:
select 'a' , sum(b) from tb where id <> 'a' or id is null
还是当tb.id='a'存在时,想得出如下的结果:
select 'a' , sum(b) from tb where id = 'a'