Question

I have two tables like this:

Date    Client  Amount | table x
123     abc     123
456     abc     987
234     xyz     567


Date    Client  Amount | table y
123     abc     234
921     lka     981
234     xyz     123

In my query, I want to display:

123     abc     123     | (from x)
123     abc     234     | (from y)
234     xyz     567     | x
234     xyz     123     | y

Leaving out all records without a “partner.” Is this possible in TSQL?

Answer 1

    select DISTINCT
           case when c='x' then x.date else y.date end date,
           case when c='x' then x.client else y.client end client,
           case when c='x' then x.amount else y.amount end amount,
           c from_
      from tablex x
      join tabley y on x.date=y.date and x.client=y.client
cross join (select 'x' union all select 'y') z(c)
  order by date, client, from_;

An alternative to the accepted solution.

Note that where you have multiple matches from either/both tables, all the results from ‘x’ will be listed before the matches from ‘y’. e.g.

create table tablex (Date int, Client char(3), Amount int);
insert tablex select
    123     ,'abc',     123 union all select
    456     ,'abc',     987 union all select
    123     ,'abc',     919 union all select
    234     ,'xyz',     567;
create table tabley (Date int, Client char(3), Amount int);
insert tabley select
    123     ,'abc',     234 union all select
    123     ,'abc',     867 union all select
    921     ,'lka',     981 union all select
    234     ,'xyz',     123;

**Results**

date        client amount      from_
----------- ------ ----------- -----
123         abc    123         x
123         abc    919         x
123         abc    234         y
123         abc    867         y
234         xyz    567         x
234         xyz    123         y