Question

我们的代码结构是这样的：

select
sampleA.columnA,
(select sampleB.columnA 
    from sampleB where sampleB.ColumnB = 'test1'),
(select sampleB.columnA 
    from sampleB where sampleB.ColumnC = 'test2')
from sampleA
join sampleB on sampleA.id = sampleB.id
where sampleA.columnB = 'test3'

如果我们只运行，那么会发生什么 select sampleB.columnA from sampleB where sampleB.ColumnB = 'test1' 然后返回27个结果。同样，它返回其他一些说35行 select sampleB.columnA from sampleB where sampleB.ColumnC = 'test2'

但是当我们运行整个查询时，我们会收到标量错误....

我们正在使用DB2并且最终希望在Jasper上运行它...并且Jasper不支持＆＃39;使用＆＃39;任何其他方式？

Answer 1

子查询必须只返回一行，请尝试：

select sampleA.columnA,
(select sampleB.columnA from sampleB where sampleB.ColumnB = 'test1' FETCH FIRST ROWS ONLY) as columnAtest1 ,
(select sampleB.columnA from sampleB where sampleB.ColumnC = 'test2' FETCH FIRST ROWS ONLY) as columnAtest2
from sampleA 
join sampleB on sampleA.id = sampleB.id
where sampleA.columnB = 'test3'

或者

select sampleA.columnA,
Samplec.columnA as columnAtest1, Sampled.columnA as columnAtest2
from sampleA 
join sampleB on sampleA.id = sampleB.id
cross join (select sampleB.columnA from sampleB where sampleB.ColumnB = 'test1' FETCH FIRST ROWS ONLY) Samplec
cross join (select sampleB.columnA from sampleB where sampleB.ColumnB = 'test2' FETCH FIRST ROWS ONLY) Sampled
where sampleA.columnB = 'test3'

db2查询：用＆＃39;替换＆＃39;

1 个答案: