if(condition, then, else) in Oracle

Question

MySQL/MSSQL has a neat little inline if function you can use within queries to detect null values, as shown below.

SELECT

...

foo.a_field AS \"a_field\",
SELEC         


        

Answer 1

Just do nvl(foo.bar,0), you don't have to do

(select nvl(foo.bar,0)... 

Answer 2

Use the standard COALESCE function:

SELECT COALESCE(foo.bar, 0) as "bar", ...

Or use Oracle's own NVL function that does the same.

Answer 3

Yup, NVL should do the trick.

Answer 4

You want the nvl function: nvl(foo.bar, 0)

Oracle does support various ifs and cases as well.

Answer 5

To supplement the rest of the answers here, which deal primarily with NULL values and COALESCE/NVL/NVL2:

SELECT *
FROM TheTable
WHERE field1 = CASE field2 WHEN 0 THEN 'abc' WHEN 1 THEN 'def' ELSE '' END

CASE statements are not as succinct, obviously, but they are geared towards flexibility. This is particularly useful when your conditions are not based on NULL-ness.

Answer 6

You want to use NVL, or NVL2

NVL(t.column, 0)
NVL2( string1, value_if_NOT_null, value_if_null )