I know that nvl
function works only for 'null', not empty string. I just wanted to know if there was a function that helps me replace blank/null values with another one.
I used instead:
CASE WHEN expression_1 is null or expression_1 = '' then expression_2 else expression_1
expression_1 column has empty cells, not null cells.
I believe you are looking Coalesce ():
Brings the first non-null value from expression2 else expression 1. If all expressions evaluate to null, then the COALESCE function will return null.
NVL function lets you substitute a value when a null value is encountered:
Sql statement would replace expression 2 with with expression 1 if it finds null value in there.
Difference: NVL always evaluates both arguments, while COALESCE usually stops evaluation whenever it finds the first non-NULL
One awesome explanation given by @Quassnoi here