SQL to combine two records into one

Question

The table I am working with uses two rows to record each 'transaction': one row to identify the party acting, the second row to identify the party acted upon. The data contents differ only in the value of one field, a logical flag of 'Y' or 'N'. For example, I might have this:

E-num  E-date       Client   Actor
1234   2013-05-02   ACME     Y
1234   2013-05-02   ALLIED   N

What I would like to report is this:

E-num  E-date       For      Against
1234   2013-05-02   ACME     ALLIED

Thanks, folks. Terry

Answer 1

just join the table on the E-num and pick the rows as required.

If you are using MySQL, the Query would be

   SELECT
     t1.E-num,
     t1.E-date,
     t1.Client AS 'For',
     t2.Client AS Against
   FROM
     `transaction` t1
   INNER JOIN
     `transaction` t2
   ON 
     t1.E-num = t2.E-num
   WHERE
     t1.Actor = 'Y' AND
     t2.Actor = 'N'

Untest, but it should give you an idea.

Answer 2

An ORACLE version: use a self-join of your table:

SELECT t1."E-num", t1."E-date", t1."Client" as "For", t2."Client" as "Against"
  FROM transaction t1, transaction t2
 WHERE t1."E-num"  = t2."E-num"
   AND t1."E-date" = t2."E-date"
   AND t1."Actor" = 'Y'
   AND t2."Actor" = 'N';

Answer 3

You could use pivot for this...

with t as (
    select [E-num] = 1234, [E-date] = '5/2/2013', [Client] = 'ACME', Actor = 'Y'
    union select 1234, '5/2/2013', 'ALLIED', 'N'
)

select
    p.[E-num],
    p.[E-date],
    [For] = p.[Y],
    [Against] = p.[N]
from
    t
    pivot (
        max(Client)
        for Actor in ([Y],[N])
    ) p