Question

How to SELECT null or blank columns in SQL

Asked by: mbroad02

I am creating an extract in SQL of some Oracle database columns.  However, when some of the columns are blank, they do not SELECT.  I would like to know how to SELECT a given column and insure that it will SELECT it even if it is blank or null.
Thank you

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Asked On
2008-03-07 at 11:49:29ID23223891
Topics

PL / SQL

,

SQL Query Syntax

Participating Experts
4
Points
475
Comments
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Answers

 

by: pollock_dPosted on 2008-03-07 at 12:04:37ID: 21073733

try something like...

SELECT NVL(column1,''),  NVL(column2,'')....etc

this will replace the NULL in the column with an empty string...\

it might work...havent tried it..

 

by: mbroad02Posted on 2008-03-07 at 12:15:43ID: 21073817

i will try this and let you know--thanks

 

by: ee_rleePosted on 2008-03-07 at 19:13:40ID: 21075712

hi, can you post your query? It might be filtered out in your WHERE condition. Try to add this

WHERE <your conditions> OR (ColumnWithNull IS NULL)

 

by: nav_kum_vPosted on 2008-03-10 at 01:04:16ID: 21084685

if you have columns with null values and you want to select them
them you have to do as shown below :

select col1, col2
from table1
where col3 is null; -- this will get all records from table1 where col3 is null.

select col1, col2
from table1
where col3 is not null; -- this will get all records from table1 where col3 is not null.

if you want to treat a null value as a different value in the queries, then we have to use
something like as shown below :

select col1, col2
from table1
where nvl(col1,9999) >= 100 ; -- i assume col1 is of number datatype

select col1, col2
from table1
where nvl(col2,'Other Dept') in ('Marketing','Other Dept') ; -- i assume col2 is of varchar2 datatype

We can even use decode, nvl2, coalesce.. to handle null values.

Thanks

 

by: mbroad02Posted on 2008-03-10 at 06:58:01ID: 21086361

Thank you for your many replies.  I am posting my query.  Notice that it is not a standard query--this one creates a fixed length text file.  
I am interested in pulling all columns in the query, whether null or not.  I do not know what columns may be null or not, so I need to check for that, and pull values if they are there, or space fill if it is null.
Please let me know how to accomplish this.

Thanks,
mark

spool  c:\extract.txt
 
SELECT RPAD(SUBSTR('D',1,1),1)
         ||     RPAD(SUBSTR(IDNT.SSN,1,9),9)
         ||     RPAD(SUBSTR('         ',1,9),9)
         ||     RPAD(SUBSTR(IDNT.LAST_NAME,1,30),30)
         ||     RPAD(SUBSTR(ADDR.ADDR_LINE1,1,30),30)
         ||     RPAD(SUBSTR(ADDR.ADDR_LINE2,1,30),30)
         ||     RPAD(SUBSTR(ADDR.CITY,1,20),20)
         ||     RPAD(SUBSTR(ADDR.ST_CD,1,2),2)
         ||     RPAD(SUBSTR(ADDR.ZIP_CD,1,9),9)
         ||     RPAD(SUBSTR('386004868',1,9),9)
         ||     RPAD(SUBSTR(' ',1,146),146)
         ||     RPAD(SUBSTR(CASE.DSCR,1,16),16)
         ||     RPAD(SUBSTR('C',1,1),1)
         ||     RPAD(SUBSTR('16  ',1,4),4)
         ||     RPAD(SUBSTR('48043',1,9),9)
         ||     RPAD(SUBSTR('0',1,1),1)
         ||     RPAD(SUBSTR('ARPTY.AMT_OUTSTANDING',1,10),10)
         ||     RPAD(SUBSTR('20080307',1,8),8)
         ||     RPAD(SUBSTR(' ',1,35),35)
 
 
 
FROM   "CRTVDBA"."ADDR" "ADDR", "CRTVDBA"."PTYADDR" "PTYADDR",
  "CRTVDBA"."IDNT" "IDNT", "CRTVDBA"."PTY" "PTY",
  "CRTVDBA"."ARPTY" "ARPTY", "CRTVDBA"."DKT" "DKT",
  "CRTVDBA"."CASE" "CASE"
 
 WHERE  ("ADDR"."ADDR_ID"="PTYADDR"."ADDR_ID" (+))
 AND ("IDNT"."IDNT_ID"="PTY"."IDNT_ID") AND
 ("PTYADDR"."CASE_ID"="PTY"."CASE_ID" (+)) AND
  ("PTY"."CASE_ID"="ARPTY"."CASE_ID" (+)) AND
  ("ARPTY"."CASE_ID"="DKT"."CASE_ID" (+)) AND
  ("DKT"."CASE_ID"="CASE"."CASE_ID" (+)) AND
  "DKT"."DKT_CD"='GICC' AND
  ("DKT"."DT">=TO_DATE ('01-09-2007 00:00:00',
  'DD-MM-YYYY HH24:MI:SS') AND
  "DKT"."DT"<TO_DATE ('02-03-2008 00:00:00',
  'DD-MM-YYYY HH24:MI:SS'));
 
	Spool off
                                              
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Select allOpen in new window

 

by: mbroad02Posted on 2008-03-10 at 08:24:50ID: 21087195

Increased point value---really need a solution--thanks

 

by: awking00Posted on 2008-03-10 at 10:11:10ID: 21088213

Substring is not needed and hard coded values need not be padded.
SELECT 'D'
      ||RPAD(NVL(IDNT.SSN,' '),9)
      ||'         '
      ||RPAD(NVL(LAST_NAME,' '),30)
      ||RPAD(NVL(ADDR.ADDR_LINE1,' '),30)
      ||RPAD(NVL(ADDR.ADDR_LINE2,' '),30)
      ||RPAD(NVL(ADDR.CITY,' '),20)
      ||RPAD(NVL(ADDR.ST_CD,' '),2)
      ||RPAD(NVL(ADDR.ZIP_CD,' '),9)
      ||'386004868'
      ||RPAD(' ',146)
      ||RPAD(NVL(CASE.DSCR,' '),16)
      ||'C'
      ||'16  '
      ||'48043    '
      ||'0'
      ||RPAD(NVL('ARPTY.AMT_OUTSTANDING',' '),10) *
      ||'20080307'
      ||RPAD(' ',35)
...

* Note - If ARPTY.AMT_OUTSTANDING is of number datatype,
 it needs to be first converted to character and probably
 right justified. -
...
      ||LPAD(NVL(TO_CHAR(ARPTY.AMT_OUTSTANDING),' '),10)
...

 

by: mbroad02Posted on 2008-03-10 at 12:41:54ID: 21089653

I am testing and will let you know shortly--thank you!

 

by: mbroad02Posted on 2008-03-10 at 13:07:40ID: 21089907

This appears to have worked!! thanks very much.
mark

 

by: mbroad02Posted on 2008-03-10 at 13:08:19ID: 31437768

Thank you!!

 

by: awking00Posted on 2008-03-11 at 05:59:34ID: 21095237

Glad to help :-)

 

by: pollock_dPosted on 2008-03-11 at 06:26:24ID: 21095429

dude, I suggested the NVL(column1,''),  NVL(column2,'')....etc .. ages ago, geez, you coulda had it working sooner...!

20120131-EE-VQP-002

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