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• MYSQL INSERT SQL WHERE RECORD IS NULL FULL

Using index Using where Full scan on NULL key Now, let’s make a NOT IN query that does not take It false, cache it and avoid the table scan at all. It’s not correlated, MySQL could instantly prove

We added an explicit check for NULL values. With a little help from our side, this can be improved: They are, but for some reason MySQL stillĪpplies the condition to each record in t_outer. It takesīut a single index scan to find out if there are Record in t_outer can satisfy the predicate. Id INT NOT NULL PRIMARY KEY AUTO_INCREMENT Now, what if inner.value is not nullable and does

Indexing have similarly optimized execution plans in In SQL, there are at least three methods toĪll these queries are semantically equivalent and with proper Just a quick reminder: an anti-join is an operation that returnsĪll records from one table which share a value of a certainĬolumn with no records from another table. Three methods to implement an anti-join in In one of the previous articles I discussed performance of the