[Solved] What happens to NULL values when you use GROUP BY on a column containing them? — Ans: All NULL values are grouped together as one group. | SQL

SQL - GROUP BY and HAVING

What happens to NULL values when you use GROUP BY on a column containing them?

AAll <code>NULL</code> values are grouped together as one group.

B<code>NULL</code> values are ignored and not included in any group.

CEach <code>NULL</code> value forms its own separate group.

D<code>GROUP BY</code> causes an error if <code>NULL</code> values exist.

Step-by-Step Solution

Solution:

Step 1: Understand how GROUP BY handles NULLs
In SQL, GROUP BY treats all NULL values in a column as equal, grouping them into one group.
Step 2: Confirm behavior with example
If a column has multiple rows with NULL, they appear as a single group in the result.
Final Answer:
All NULL values are grouped together as one group. -> Option A
Quick Check:
GROUP BY NULL = one group [OK]

Quick Trick: Remember: NULLs group together, not separately [OK]

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What happens to NULL values when you use GROUP BY on a column containing them?