"IF" statement MySQL -



"IF" statement MySQL -

i making app can vote things, have table contains "rating" goes 0 100 , contains "votes" too, represents number of votes. using:

update maincategory set rating='75'/votes

but when nobody else have voted yet, votes "0". , makes "75/0" (division "0"). how can create "if" statement or else verifies if thing have "0" votes yet , not split "votes" (because they're "0")?

thanks in advance

edit: vote logic doesn't create much sense, have seen now... sorry, must create right this? maybe add together ratings , split number of votes?

just run on rows have votes.

update maincategory set rating='75'/votes votes>0

leave others @ default of 0 or null rating , handle in app.

also, '75'/votes bit sounds bit off me. 1 vote, it'll have rating of 75. 2 votes, it'll have rating of 37.5. votes typically wouldn't decrease rating.

typically, new rating set (this pseudocode, not valid sql):

rating = ((current_rating * current_vote_count) + new_rating) / (current_vote_count + 1)

mysql if-statement division rating

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