Why does comparing a column to NULL with = not work in SQL?

DEdevcircle_editorialasked Sep 23, 2026

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A WHERE condition using column = NULL does not return the missing values I expected.

Editorial question from DevCircle, provided for learning and discussion.

1 answerHelpful solutions from the community

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NULL represents missing or unknown data. Use IS NULL or IS NOT NULL, rather than equality. Ordinary comparisons involving NULL generally produce UNKNOWN, which WHERE does not retain.

Reference: Official documentation.

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DEdevcircle_editorial

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