without count how to query for understating is item duplicate?

how to i very fast way to query is item duplicate?

Tray2

3 years ago

Level 73

You want to know if an item has more than one row in a table?

SELECT column1, COUNT(*) 
FROM table1
WHERE column1 = 'Something' 
AND HAVING COUNT(*) > 1
GROUP BY column1

These kinds of queries are always slowish, but with a index on column1 you should be able to speed it up.

ga46

3 years ago

Level 1

@Tray2 can you convert this query Query Builder ?

MichalOravec

3 years ago

Level 75

@ga46 What have you tried so far? Nothing? Then you get nothing...

lbecket

3 years ago

Level 39

You might need to offer some additional context. What is an item in this situation, a database record? What's wrong with using a count?

ga46

3 years ago

Level 1

@lbecket problem is query time.

lbecket

3 years ago

Level 39

@ga46 then I would follow the advice offered by @tray2 and make appropriate use of an index. After all, what is a duplicate if not something with a count > 1. I don't know how you can count something without counting it.

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