MDEV-37933: Rewrite [NATURAL] FULL OUTER to LEFT, RIGHT, or INNER JOIN #4448
+784
−61
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
DaveGosselin-MariaDB
force-pushed
the
12.3-MDEV-37933-outer-to-left-right-or-inner
branch
from
2f6bff2 to
bf2f3ad
Compare
Rewrite FULL OUTER JOIN queries as either LEFT, RIGHT, or INNER JOIN by checking if and how the WHERE clause rejects nulls. For example, the following two queries are equivalent because the WHERE condition rejects nulls from the left table and allows matches in the right table (or NULL from the right table) for the remaining rows: SELECT * FROM t1 FULL JOIN t2 ON t1.v = t2.v WHERE t1.v IS NOT NULL; SELECT * FROM t1 LEFT JOIN t2 ON t1.v = t2.v;
DaveGosselin-MariaDB
force-pushed
the
12.3-MDEV-37933-outer-to-left-right-or-inner
branch
from
bf2f3ad to
e3f59c1
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Rewrite FULL OUTER JOIN queries as either LEFT, RIGHT, or INNER JOIN by checking if and how the WHERE clause rejects nulls.
For example, the following two queries are equivalent because the WHERE condition rejects nulls from the left table and allows matches in the right table (or NULL from the right table) for the remaining rows: