Question

我有下表：

table_user_1
col6        member_records
123         5
456         6
222         4

table_user_2
col5        member_records
554         5
456         6
124         4

table_user_3
col7        member_records
123         5
755         6
449         4

我想查看所有用户联合，然后检查表中是否存在该用户。

为了工会，我尝试过：

select col6 from table_user_1
union
select col5 from table_user_2
union
select col7 from table_user_3;

输出应为：

member     table_user_1       table_user_2      table_user_3
123        1                  0                 1
456        1                  1                 0
222        1                  0                 0
554        0                  1                 0
124        1                  1                 0
755        1                  0                 1
449        1                  0                 1

如何生成上述输出？

Answer 1

with table_user_1(col6, member_records) as (
select 123, 5 from dual union all
select 456, 6 from dual union all
select 222, 4 from dual),

table_user_2(col5, member_records) as (
select 554, 5 from dual union all
select 456, 6 from dual union all
select 124, 4 from dual),

table_user_3(col7, member_records) as (
select 123, 5 from dual union all
select 755, 6 from dual union all
select 449, 4 from dual)

select *
from
   (select col6, 1 as table_id from table_user_1
    union all
    select col5, 2 from table_user_2
    union all
    select col7, 3 from table_user_3
   )
pivot(count(*) for table_id in (1 as table_user_1, 2 table_user_2, 3 as table_user_3));

      COL6 TABLE_USER_1 TABLE_USER_2 TABLE_USER_3
---------- ------------ ------------ ------------
       123            1            0            1
       222            1            0            0
       554            0            1            0
       755            0            0            1
       456            1            1            0
       449            0            0            1
       124            0            1            0

Answer 2

使用联合和左联接

select a.id as member,nvl2(t1.col6,1,0) as table1,
  nvl2(t2.col5,1,0) as tbale2,
  nvl2(t3.col7,1,0) as table3 from 
(select col6 as id from table_user_1
union
select col5 from table_user_2
union
select col7 from table_user_3
) a left join table_user_1 t1 on a.id=t1.col6
    left join table_user_2  t2 on a.id=t2.col5
    left join table_user_3 t3 on a.id=t3.col7

Answer 3

一种选择是使用条件聚合：

select member,
       max( case when col0 = 1 then 1 else 0 end ) as table_user_1,
       max( case when col0 = 2 then 1 else 0 end ) as table_user_2,
       max( case when col0 = 3 then 1 else 0 end ) as table_user_3 
  from
(
  select 1 col0, col6 as member
    from table_user_1
  union all
  select 2 col0, col5
    from table_user_2
  union all
  select 3 col0, col7
    from table_user_3 ) q
group by member;

Demo

Answer 4

您可以使用full join：

select coalesce(t1.col5, t2.col6, t3.col7) as member,
       nvl2(t1.col5, 1, 0) as in_t1,
       nvl2(t2.col6, 1, 0) as in_t2,
       nvl2(t3.col7, 1, 0) as in_t3
from table_user_1 t1 full join
     table_user_2 t2
     on t2.col6 = t1.col5 full join
     table_user_3 t3
     on t3.col7 in (t1.col5, t2.col6);

或者，您可以使用group by和union all：

select member,
       max(t1), max(t2), max(t3)
from ((select col5 as member, 1 as t1, 0 as t2, 0 as t3
       from table_user_1
      ) union all
      (select col6, 0 as t1, 1 as t2, 0 as t3
       from table_user_2
      ) union all
      (select col7, 0 as t1, 0 as t2, 2 as t3
       from table_user_3
      ) 
     ) x
group by member;

检查多个表中是否存在值-Oracle SQL

4 个答案: