Question : Informix SQL "is null" syntax

I have a table column that contains blank values and null values I want it to only display blank values

I am used to SQL syntax not informix I believe the below would work in SQL how can it work in informix?

select column1, column2, IS NULL(column3, "") as 'column3 no nulls'
from table1

Answer : Informix SQL "is null" syntax

select column1, column2, NVL(column3, "") as 'column3 no nulls'
from table1