Missing Expression Error When Case Statment is used as field

Question

I have tried to write an expression that will calculate how many days ago a request was submitted and return a user defined value if the calculation falls within the criteria in the case statment. The SQL View for the Query I am using is shown below:
SELECT A.F_POSN_REQUEST_ID, A.F_REQ_ECP_STATUS, TO_CHAR(A.REQUEST_DTTM,'YYYY-MM-DD-HH24.MI.SS."000000"'), TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'), TO_CHAR(A.F_REQ_ECP_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'), TO_CHAR(A.F_REQ_ECP_PROC_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'), CASE WHEN(sysdate - TO_DATE(SUBSTR( TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),1,16),'YYYY-MM-DD-HH24.MI'))>60 THEN '>60' ELSE(CASE WHEN(sysdate - TO_DATE(SUBSTR( TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),1,16),'YYYY-MM-DD-HH24.MI')) >30 AND <=60 THEN '30 - 60' ELSE(CASE WHEN(sysdate - TO_DATE(SUBSTR( TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),1,16),'YYYY-MM-DD-HH24.MI'))>=15 AND <=30 THEN '15 - 30' ELSE(CASE WHEN(sysdate - TO_DATE(SUBSTR( TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),1,16),'YYYY-MM-DD-HH24.MI'))<15 THEN 'Less Than 15' ELSE NULL END)END)END)END))
  FROM PS_F_POSN_REQUEST A
  WHERE A.F_REQ_ECP_STATUS IN ('I','O','P')
  GROUP BY  A.F_POSN_REQUEST_ID,  A.F_REQ_ECP_STATUS,  TO_CHAR(A.REQUEST_DTTM,'YYYY-MM-DD-HH24.MI.SS."000000"'),  TO_CHAR(A.F_REQ_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),  TO_CHAR(A.F_REQ_ECP_ST_DT,'YYYY-MM-DD-HH24.MI.SS."000000"'),  TO_CHAR(A.F_REQ_ECP_PROC_DT,'YYYY-MM-DD-HH24.MI.SS."000000"')When I try to run the query I get Message=ORA-00936: missing expression (50,380)
Any suggestions you could provide to help me clear this error would be greatly appreciated.
Edited by: 992737 on Mar 8, 2013 9:07 AM

Answer 1

Hi,
Welcome to the forum!
I think you want something like this:
CASE
    WHEN  a.f_req_st_dt < TRUNC (SYSDATE) - 60  THEN  '>60'
    WHEN  a.f_req_st_dt < TRUNC (SYSDATE) - 30  THEN  '30.1-60'
    WHEN  a.f_req_st_dt < TRUNC (SYSDATE) - 15  THEN  '15.1-30'
    WHEN  a.f_req_st_dt < TRUNC (SYSDATE)       THEN  '15 or less'
ENDNested CASE expressions aren't needed very much. Each WHEN clause is evaluated only if all the ealier ones have failed. For example, when testing to see if a row is in the 301.-60 range above (that is, the 2nd WHEN clause), there's no need to see if the difference is greater than or equal to 60; it wouldn't be evaluating that clause if the 1st WHEN condition was TRUE.
This assumes that a.f_req_st_dt is a TIMESTAMP or DATE; either datatype can be compared with DATEs, such as SYSDATE-60, so there's no need to conevert them to strings, and then convert them back into DATEs.
I hope this answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements, relevant columns only) for all tables involved, and also post the results you want from that data.
Simplify the problem as much as possible. Show only the parts that you don't already know how to do.
Explain, using specific examples, how you get those results from that data.
Always say which version of Oracle you're using (e.g., 11.2.0.2.0).
See the forum FAQ {message:id=9360002}
Never write, let alone post, unformatted code. Indent the code to show the exent and structure of clauses (SELECT, FROM, etc.), and complex expressions (such as CASE). The forum FAQ explains how to use \ tags when posting formatted text on this site.