Difference between revisions of "NVL"

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Line 24: Line 24:
 
SELECT name, party
 
SELECT name, party
 
       ,NVL(party,'None') AS aff
 
       ,NVL(party,'None') AS aff
   FROM msp WHERE name LIKE 'C%'
+
   FROM gisq.msp WHERE name LIKE 'C%'
 
</source>
 
</source>
 
<source lang='sql' class='def'>
 
<source lang='sql' class='def'>

Revision as of 15:13, 16 July 2012

Compatibility
NVL(f1, f2)
EngineOKAlternative
ingresNoCOALESCE(f1, f2)
mysqlNoCOALESCE(f1, f2)
oracleYesCOALESCE(f1, f2)
postgresNoCOALESCE(f1, f2)
sqlserverNoCOALESCE(f1, f2)

NVL

NVL takes two arguments and returns the first value that is not null.

   NVL(x,y) = x if x is not NULL
   NVL(x,y) = y if x is NULL

NVL can be useful when you want to replace a NULL value with some other value. In this example you show the name of the party for each MSP that has a party. For the MSP with no party (such as Canavan, Dennis) you show the string None.

SELECT name, party
      ,NVL(party,'None') AS aff
  FROM gisq.msp WHERE name LIKE 'C%'
SELECT name, party
      ,COALESCE(party,'None') AS aff
  FROM msp WHERE name LIKE 'C%'

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