Here are two query structures I’m considering:
LEFT JOIN followed by WHERE:
SELECT *
FROM table1
LEFT JOIN table2 ON table1.id = table2.id
WHERE table2.column = 'value';
WHERE followed by LEFT JOIN:
SELECT *
FROM table1
WHERE table1.column = 'value'
LEFT JOIN table2 ON table1.id = table2.id;
- Does the optimizer treat these two queries differently, or does it optimize them to be equivalent?
- Are there any performance implications or best practices regarding the order of LEFT JOIN and WHERE clauses?
I understand that MySQL’s query optimizer is supposed to handle the execution order efficiently, but I’m interested in whether there is a performance difference in these two approaches, especially for complex queries with multiple joins and filtering conditions.
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