Which would be faster?
Method A:
UPDATE table1
SET table1.column1 = table2.column1
FROM table2
WHERE table1.column2 = table2.column2
Method B:
UPDATE table1
SET table1.column1 = table2.column1
FROM table1
JOIN table2 on table1.column2 = table2.column2
Will they generate the same execution plan?
Is there any case where I should avoid one of them?
Some tests I did took them almost the same time to execute, but always good to hear a second opnion.
They are equivalent. You can verify this by checking the execution plan yourself. The second option:
UPDATE table1
SET table1.column1 = table2.column1
FROM table1 JOIN
table2 on table1.column2 = table2.column2
Is currently the preferred method for writing queries, as it's more clear why the criteria is being specified.
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