Question

我有2张这样的表（简化示例）：

create table T (i integer, a text);
insert into T values (3,'ww');
insert into T values (1,'ee');
insert into T values (5,'nn');
insert into T values (2,'kk');
insert into T values (4,'ss');

create table U (i integer);
insert into U values (2);
insert into U values (3);
insert into U values (5);
insert into U values (1);

select rowid, i from U;
rowid  i
----- --
    1  2
    2  3
    3  5
    4  1

select * from T where i in (select i from U order by rowid);
    i                a
----- ----------------
    3               ww
    5               nn
    2               kk  
    1               ee

我需要i中收集的in(...)与内部选择的顺序相同，如：

select * from T where i inUnsorted (select i from U order by rowid);
    i                a
----- ----------------
    2               kk          
    3               ww
    5               nn
    1               ee

这可能吗？

Answer 1

在SQL中，除非您使用ORDER BY，否则查询是未排序的，因此外部查询需要此子句。

无论如何，您只需使用相关子查询查找值：

SELECT *
FROM T
WHERE i IN (SELECT i
            FROM U)
ORDER BY (SELECT rowid
          FROM U
          WHERE U.i = T.i);

Answer 2

这方面的东西，但更简单，即删除临时表

create temp table T2  as select i,0 as f from T;
update T2 set f=(select rowid from U where U.i=T2.i);
select * from T2;
    i                f
----- ----------------
    3                2
    1                4
    5                3
    2                1
    4

select T.i,a from T join T2 on T.i=T2.i where T2.f order by T2.f;
    i                a
----- ----------------
    2               kk
    3               ww
    5               nn
    1               ee

Answer 3

我对这个问题感到困惑。但如果我猜对了，这应该是你想要的？

select T.*, U.i as ui from T inner join U on T.i = U.i;

按另一列的顺序选择表的子集

3 个答案: