如何将外键表的总和作为select语句中主表行的值?
考虑表1:
id(PK) name description
-----------------------------
1 test1 desc1
2 test2 desc2
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表2是:
id(FK) value
-----------------
1 5
1 6
2 7
2 8
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SQL select语句的结果应该是这样的
id name desc sum(value)
----------------------------------
1 test1 desc1 11
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select
t.*,
( select
sum(tt.value)
from table2 tt
where tt.id = t.id) sum_value
from table1
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HTH