Question

Column 1:

( CASE
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'General' THEN 'G'
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Honors' THEN 'H'
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'WhosWho' THEN 'Y'
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Catholic' THEN 'J'
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Conservative' THEN 'B'
           ELSE 'H'
         END )                        AS Edition

Column 2:

(SELECT edition
        FROM   clients.dbo.service
        WHERE  serv_id = hdr.serv_id) AS editiontext,
       ( CASE
           WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
           ELSE ( CASE
                    WHEN si.itmclass = 'Distrib' THEN '-Disc'
                    WHEN si.itmclass = 'PremIR' THEN '0' + '-Disc'
                    WHEN si.itmclass = 'InstResp' THEN '5' + '-Disc'
                    ELSE ''
                  END )
         END )                        AS 'ItemCode'

I need to combine both Edition and ItemCode in a third column. -Disc (ItemCode) should becone like G-Disc but 0-Disc (ItemCode) should become like 0G-Disc.

I need the select as

Select Edition, ItemCode, Edition+ItemCode….

I have used following to create the third column but curious if this could be done in a better way…

( CASE
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'General' THEN (
           CASE
             WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
             ELSE( CASE
                     WHEN si.itmclass = 'Distrib' THEN 'G-Disc'
                     WHEN si.itmclass = 'PremIR' THEN '0G' + '-Disc'
                     WHEN si.itmclass = 'InstResp' THEN '5G' + '-Disc'
                     ELSE ''
                   END )
           END )
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Honors' THEN (
           CASE
             WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
             ELSE( CASE
                     WHEN si.itmclass = 'Distrib' THEN 'H-Disc'
                     WHEN si.itmclass = 'PremIR' THEN '0H' + '-Disc'
                     WHEN si.itmclass = 'InstResp' THEN '5H' + '-Disc'
                     ELSE ''
                   END )
           END )
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'WhosWho' THEN (
           CASE
             WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
             ELSE( CASE
                     WHEN si.itmclass = 'Distrib' THEN 'Y-Disc'
                     WHEN si.itmclass = 'PremIR' THEN '0Y' + '-Disc'
                     WHEN si.itmclass = 'InstResp' THEN '5Y' + '-Disc'
                     ELSE ''
                   END )
           END )
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Catholic' THEN (
           CASE
             WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
             ELSE( CASE
                     WHEN si.itmclass = 'Distrib' THEN 'J-Disc'
                     WHEN si.itmclass = 'PremIR' THEN '0J' + '-Disc'
                     WHEN si.itmclass = 'InstResp' THEN '5J' + '-Disc'
                     ELSE ''
                   END )
           END )
           WHEN (SELECT edition
                 FROM   clients.dbo.service
                 WHERE  serv_id = hdr.serv_id) = 'Conservative' THEN (
           CASE
             WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
             ELSE( CASE
                     WHEN si.itmclass = 'Distrib' THEN 'B-Disc'
                     WHEN si.itmclass = 'PremIR' THEN '0B' + '-Disc'
                     WHEN si.itmclass = 'InstResp' THEN '5B' + '-Disc'
                     ELSE ''
                   END )
           END )
           ELSE ( CASE
                    WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
                    ELSE( CASE
                            WHEN si.itmclass = 'Distrib' THEN 'H-Disc'
                            WHEN si.itmclass = 'PremIR' THEN '0H' + '-Disc'
                            WHEN si.itmclass = 'InstResp' THEN '5H' + '-Disc'
                            ELSE ''
                          END )
                  END )
         END )                        AS EditionItemCode

Answer 1

You have a number of redundant subqueries in your case statement that I don’t think need to be there. If I understand your tables and queries correct, you should be able to do the following instead. Note I have pulled out the first case statement (Edition column) into a derived-table join, then reference it from the second case statement to make EditionItemCode.

SELECT s.edition AS editiontext, s.e AS edition,
    CASE
        WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
        WHEN si.itmclass = 'Distrib' THEN '-Disc'
        WHEN si.itmclass = 'PremIR' THEN '0-Disc'
        WHEN si.itmclass = 'InstResp' THEN '5-Disc'
        ELSE ''
    END AS ItemCode,
    CASE
        WHEN hdr.giftcarddiscount = 1 THEN 'GCDisc'
        WHEN si.itmclass = 'Distrib' THEN s.e + '-Disc'
        WHEN si.itmclass = 'PremIR' THEN '0' + s.e + '-Disc'
        WHEN si.itmclass = 'InstResp' THEN '5' + s.e + '-Disc'
        ELSE ''
    END AS EditionItemCode
FROM hdr
LEFT OUTER JOIN
(
    SELECT serv_id, CASE edition
               WHEN 'General' THEN 'G'
               WHEN 'Honors' THEN 'H'
               WHEN 'WhosWho' THEN 'Y'
               WHEN 'Catholic' THEN 'J'
               WHEN 'Conservative' THEN 'B'
               ELSE 'H'
          END AS e, edition
    FROM clients.dbo.service
) s ON s.serv_id = hdr.serv_id
JOIN si ON ...