Check out example codes for "check record not nul in sql". It will help you in understanding the concepts better.

Code Example 1

SELECT column_names
FROM table_name
WHERE column_name IS NOT NULL;

Code Example 2

SELECT column_names
FROM table_name

  WHERE column_name IS NULL;

Code Example 3

SELECT column_names
FROM table_name

  WHERE column_name IS NOT NULL;

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