SQLite equivalent to ISNULL(), NVL(), IFNULL() or COALESCE()

Question

I\'d like to avoid having many checks like the following in my code:

myObj.someStringField = rdr.IsDBNull(someOrdinal) 
                            ? string.         


        

Answer 1

You can easily define such function and use it then:

ifnull <- function(x,y) {
  if(is.na(x)==TRUE) 
    return (y)
  else 
    return (x);
}

or same minified version:

ifnull <- function(x,y) {if(is.na(x)==TRUE) return (y) else return (x);}

Answer 2

For the equivalent of NVL() and ISNULL() use:

IFNULL(column, altValue)

column : The column you are evaluating.

altValue : The value you want to return if 'column' is null.

Example:

SELECT IFNULL(middle_name, 'N/A') FROM person;

*Note: The COALESCE() function works the same as it does for other databases.

Sources:

• COALESCE() Function (w3schools)
• SQL As Understood By SQLite (SQLite website)

Answer 3

Use IS NULL or IS NOT NULL in WHERE-clause instead of ISNULL() method:

SELECT myField1
FROM myTable1
WHERE myField1 IS NOT NULL

Answer 4

Try this

ifnull(X,Y)  

e.g

select ifnull(InfoDetail,'') InfoDetail; -- this will replace null with ''
select ifnull(NULL,'THIS IS NULL');-- More clearly....

The ifnull() function returns a copy of its first non-NULL argument, or NULL if both arguments are NULL. Ifnull() must have exactly 2 arguments. The ifnull() function is equivalent to coalesce() with two arguments.

Answer 5

If there is not ISNULL() method, you can use this expression instead:

CASE WHEN fieldname IS NULL THEN 0 ELSE fieldname END

This works the same as ISNULL(fieldname, 0).

Answer 6

IFNULL, see here: http://www.sqlite.org/lang_corefunc.html#ifnull

no brackets around the function