Difference between revisions of "NVL"
From SQLZOO
| 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 16:13, 16 July 2012
| NVL(f1, f2) | ||
|---|---|---|
| Engine | OK | Alternative |
| ingres | No | COALESCE(f1, f2) |
| mysql | No | COALESCE(f1, f2) |
| oracle | Yes | COALESCE(f1, f2) |
| postgres | No | COALESCE(f1, f2) |
| sqlserver | No | COALESCE(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%'
See also
