EMPTY CHECK IN SQL code example

Example 1: sql not null

SELECT column_name FROM table_name 
WHERE column_name IS NOT NULL;

Example 2: sql check for null and empty string

IF ISNULL(@param) OR @param = '' THEN doSomething...

Example 3: sql if empty then

SELECT COALESCE(NULLIF(SomeColumn,''), ReplacementColumn)
FROM SomeTable

Example 4: sql is null

Tests for empty (NULL) values.
Example: Returns users that haven’t given a contact number.
SELECT * FROM users
WHERE contact_number IS NULL;