Query block has incorrect number of result columns

Question

can anyone edit my query to eliminate below error ??
SELECT FLROOPENHEAD.RONBR RepairOrder,FLROOPENHEAD.DATEOPENED DateOpened,NULL DateClosed,
(SELECT FLREPAIRSTAT.DESCRIPTION  FROM FLREPAIRSTAT
WHERE FLREPAIRSTAT.REPAIRSTATID = FLROOPENHEAD.REPAIRSTATID) RepairOrderStatus,
  (SELECT flrt.DESCRIPTION FROM FLREPAIRTYPE flrt
  WHERE flrt.REPAIRTYPEID = FLROOPENHEAD.REPAIRTYPEID) RepairType,  FLROOPENHEAD.REPAIRCENTER  RepairCenter,
FLROOPENHEAD.FLVEHICLEID , FLROOPENHEAD.FLATTACHID,'O'
FROM FLROOPENHEAD   WHERE FLROOPENHEAD.LDEVNBR =2334
AND ((extract(DAY FROM SYSTIMESTAMP - TIMEOPENED)*24)+(extract(HOUR FROM SYSTIMESTAMP - TIMEOPENED)) <= 72)
UNION
SELECT FLROHISTHEAD.RONBR RepairOrder,FLROHISTHEAD.DATEOPENED DateOpened, null, FLROHISTHEAD.DATECLOSED DateClosed,
(SELECT FLREPAIRSTAT.DESCRIPTION  FROM FLREPAIRSTAT
WHERE FLREPAIRSTAT.REPAIRSTATID =FLROHISTHEAD.REPAIRSTATID) RepairOrderStatus,
(SELECT flrt.DESCRIPTION FROM FLREPAIRTYPE flrt
WHERE flrt.REPAIRTYPEID = FLROHISTHEAD.REPAIRTYPEID) RepairType, FLROHISTHEAD.REPAIRCENTER  RepairCenter
from FLROHISTHEAD WHERE FLROHISTHEAD.LDEVNBR =2334
AND ((extract(DAY FROM SYSTIMESTAMP - FLROHISTHEAD.TIMECLOSED)*24) + (extract(HOUR FROM SYSTIMESTAMP - FLROHISTHEAD.TIMECLOSED)) <= 72)
ORDER BY DateOpened, RepairOrder
i think error was at second Where condition.
Error at Command Line:1 Column:0
Error report:
SQL Error: ORA-01789: query block has incorrect number of result columns
01789. 00000 -  "query block has incorrect number of result columns"
*Cause:   
*Action:

Answer 1

Hi,
On comparison with 1st query and 2nd query,it can be easily noticed that ,1st query is returning 4 columns and 2nd query returns 5 columns in select clause.
In order to work union ,both of your queries should select equal no of columns.
Hence replace your query
Original query(1st ) :
SELECT FLROOPENHEAD.RONBR RepairOrder,FLROOPENHEAD.DATEOPENED DateOpened,NULL DateClosed,
(SELECT FLREPAIRSTAT.DESCRIPTION  FROM FLREPAIRSTAT
WHERE FLREPAIRSTAT.REPAIRSTATID = FLROOPENHEAD.REPAIRSTATID) RepairOrderStatus,
....Relplace with :
SELECT FLROOPENHEAD.RONBR RepairOrder,FLROOPENHEAD.DATEOPENED DateOpened,NULL,/*Here you need missed the comma */
DateClosed,
(SELECT FLREPAIRSTAT.DESCRIPTION  FROM FLREPAIRSTAT
WHERE FLREPAIRSTAT.REPAIRSTATID = FLROOPENHEAD.REPAIRSTATID) RepairOrderStatus,
....Hope this helps
Regards,
Achyut