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Question

I am trying to union two queries to show the top 5 customer codes but I keep receiving an error, SQLSTATE 42601 . Ideally I would like the query to show something like this.

LTIHONIA CLIENT 1 1330
LITHOINA CLIENT 2 1300
LITHONIA CLIENT 3 1000
ATHENS CLIENT 1 1330
ATHENS CLIENT 2 1000
ATHENS CLIENT 3 400 

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SELECT 'LITHONIA' AS TYPE,  CLIENT_ID, ROUND(DEC(SUM(ORIG_AMT)),2) AS REVENUE FROM AR_SUM AR, TLORDER WHERE AGING_DATE >= '1/1/2016' AND AR.BILL_NUMBER = TLORDER.BILL_NUMBER 
AND CURRENT_STATUS IN ('BILLD','EDIBILLED') AND ORIG_AMT > 0 AND AR.SITE_ID = 'SITE1' 
GROUP BY CLIENT_ID
ORDER BY REVENUE DESC 
FETCH FIRST 5 ROWS ONLY
UNION 
SELECT 'LITHONIA' AS TYPE,  CLIENT_ID, ROUND(DEC(SUM(ORIG_AMT)),2) AS REVENUE FROM AR_SUM AR, TLORDER WHERE AGING_DATE >= '1/1/2016' AND AR.BILL_NUMBER = TLORDER.BILL_NUMBER 
AND CURRENT_STATUS IN ('BILLD','EDIBILLED') AND ORIG_AMT > 0 AND AR.SITE_ID = 'SITE10' 
GROUP BY CLIENT_ID
ORDER BY REVENUE DESC 
FETCH FIRST 5 ROWS ONLY

Answer 1

Try using parentheses around the subqueries:

(SELECT 'LITHONIA' AS TYPE,  CLIENT_ID, ROUND(DEC(SUM(ORIG_AMT)),2) AS REVENUE
 FROM AR_SUM AR JOIN
      TLORDER
      ON  AR.BILL_NUMBER = TLORDER.BILL_NUMBER
 WHERE AGING_DATE >= '1/1/2016' AND CURRENT_STATUS IN ('BILLD','EDIBILLED') AND ORIG_AMT > 0 AND AR.SITE_ID = 'SITE1' 
 GROUP BY CLIENT_ID
 ORDER BY REVENUE DESC 
 FETCH FIRST 5 ROWS ONLY
) UNION 
(SELECT 'LITHONIA' AS TYPE,  CLIENT_ID, ROUND(DEC(SUM(ORIG_AMT)),2) AS REVENUE  
 FROM AR_SUM AR JOIN
      TLORDER
      ON AR.BILL_NUMBER = TLORDER.BILL_NUMBER 
 WHERE AGING_DATE >= '1/1/2016' AND 
       CURRENT_STATUS IN ('BILLD','EDIBILLED') AND ORIG_AMT > 0 AND AR.SITE_ID = 'SITE10' 
 GROUP BY CLIENT_ID
 ORDER BY REVENUE DESC 
 FETCH FIRST 5 ROWS ONLY
)

Also, you should learn to use proper explicit JOIN syntax. Simple rule: Never use commas in the FROM clause. And, UNION ALL is probably more appropriate than UNION , unless you intend for duplicates to be removed.

Answer 2

@OVO

I am sure that your query has error 42601 due to order by clause. You cant have it in union query. Remove order by clause from both sqls & put then like select fields from (YOUR UNION SQL) order by bla bla.