mysql - Understanding this query (COUNT & subquery) -
i'm having trouble understanding query:
select * `advertise` parent 3 <= ( select count(username) `advertise` keyword = parent.keyword , bid > parent.bid) , username = 'mike'
what query display rows username 'mike'
; if row not in 3 highest bids keyword.
here sqlfiddle works, don't understand how works. more don't understand 3 <=
specific query.
how 3 <=
determine row not in 3 highest bids keyword?
this query works so:
the subquery
select count(username) `advertise` keyword = parent.keyword , bid > parent.bid
finds number of rows have higher bid same keyword. specify bid looking cannot in top 3 bids, require @ least 3 bids returned query. here think end query should like:
select * `advertise` parent 3 <= ( select count(username) `advertise` keyword = parent.keyword , bid > parent.bid) , username = 'mike'
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