varchar join integer

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varchar join integer

Consider two tables ,one has COLUMN_A defined as a VARCHAR(100) and the other has COLUMN_A defined as an INTEGER. When joining these two tables via COLUMN_A what does the optimizer have to do in order to accomplish the join?Convert VARCHAR to INTEGER  or convert INTEGER to VARCHAR? thanks.

1 REPLY
Junior Contributor

Re: varchar join integer

When you look at Explain you will see that the VARCHAR is casted to a FLOAT.