If I use a mysql function in a where clause that returns a static value does it get re-evaluated every row?

For example,

select * from x where crc=CRC32('Hi')

does the CRC32 function get run every row it checks? If so how could 开发者_开发知识库I optimize it?

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if you didn't pass row values as arguments it will be evaluated once.

except for this case:

SELECT column FROM table
ORDER BY RAND()
LIMIT 1

selecting random row