Missing matches appear as NULL-valued columns.
Section: NULL behavior
Expect NULLs on the optional side of outer joins
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LEFT JOIN → right-side columns may be NULL
RIGHT JOIN → left-side columns may be NULL
FULL OUTER JOIN → either side may be NULLExplanation
This is normal and often what makes outer joins useful.
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Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.
Related commands
Same sheet · prioritizing NULL behavior
Use COALESCE for outer-join aggregates
Replace `NULL` with a friendlier value in results.
Use COUNT(DISTINCT ...) when joins multiply rows
Protect aggregates from one-to-many duplication.