Question

我有这些多个sql查询，我想将它们捆绑到一个单独的查询中，这样我就可以避免从我的应用程序向数据库发送多个请求（我希望一次性接收所有这些数据）：< / p>

1) select pin, officeNum, isVeteran from table18 where pin = 123;

2) select streetAddress, apartmentAddress, cityAddress, stateAddress from table1 where case = (select case from table18 where pin = 123);

3) select unitAddress, cityAddress, streetAddress, apartmentAddress from table5 where pin = 123;

4) select unitAddress, cityAddress, streetAddress, apartmentAddress from table55 where seqNum = 0 and rfa = (select rfa from table18 where pin = 123);

5) select unitAddress, cityAddress, streetAddress, apartmentAddress from table103 where histCode = 0 and case = (select case from table18 where pin = 123);

6) select phone, email from table715 where histSeqNum in (select max(histSeqNum from table715))
      and histCode in (select max(histCode) from table715)
      and case = (select case from table18 where pin = 123);

这是我的架构：

（请原谅糟糕的设计，它来自20年前创建的数据库，没有外键）

-Table18（pin（PK），case，officeNum，isVeteran）

-Table1（case（PK），caseOfficer，streetAddress，apartmentAddress，cityAddress，stateAddress）

-Table5（pin（PK），streetAddress，apartmentAddress，cityAddress，stateAddress）

-Table55（rfa（CompositeKey），seqNum（CompositeKey），rfaAddress，streetAddress，apartmentAddress，cityAddress，stateAddress）

-Table103（case（CompositeKey），histCode（CompositeKey））

-Table715（case（CompositeKey），histSeqNum（CompositeKey），histCode（CompositeKey），电话，电子邮件）

Answer 1

你做不到。所有查询都返回固定数量的列。如果仍然坚持以这种方式检索列，请确保所有查询的columns数据类型相同，并将它们与联合组合。我不建议这样做，但这是可能的。

Answer 2

这是一个可以联合的集合...... （3,4,5）

select unitAddress, cityAddress, streetAddress, apartmentAddress 
from table5 where pin = 123
union
select unitAddress, cityAddress, streetAddress, apartmentAddress 
from table55 where seqNum = 0 and rfa = (select rfa from table18 where pin = 123)
union
select unitAddress, cityAddress, streetAddress, apartmentAddress 
from table103 where histCode = 0 and case = (select case from table18 where pin = 123);

如果你不介意这些空白状态，你可以把（2）放在那里......

例如，在2中写下类似的东西：

select null unitAddress, streetAddress, apartmentAddress, cityAddress, stateAddress 
from table1 
where case = (select case from table18 where pin = 123);
union
select unitAddress, cityAddress, streetAddress, apartmentAddress, null
from table5 where pin = 123
union
select unitAddress, cityAddress, streetAddress, apartmentAddress, null 
from table55 where seqNum = 0 and rfa = (select rfa from table18 where pin = 123)
union
select unitAddress, cityAddress, streetAddress, apartmentAddress, null
from table103 where histCode = 0 and case = (select case from table18 where pin = 123);

还考虑重组你的嵌套选择加入 - 类似于:(我打赌优化这些查询将是你正在寻找的性能差异）

select streetAddress, apartmentAddress, cityAddress, stateAddress 
from table1  t1, table18 t18
where t1.case = t18.case 
and t18.123;

然后确保t18在引脚上有一个索引，而t1在case上有一个索引。

如何将多个SQL查询合并为一个？

2 个答案: