Question

I have a MySQL table where two of the fields are supposed to be unique. As new data is offered up I need to check if it already exists, and so would like to do something like (PDO parameters included):

SELECT COUNT(foo),COUNT(bar) 
FROM `mytable` 
WHERE foo=:foo 
OR bar=:bar;

The problem here is that if both values will come back with identical counts, so in the event of that count being 1 I don’t know which column contains the matching value. Obviously I could split this into 2 queries, but is there a neater way to check both at once?

Answer 1

Maybe something like this:

SELECT
    SUM(CASE WHEN foo='foo' THEN 1 ELSE 0 END) AS FooCount,
    SUM(CASE WHEN bar='bar' THEN 1 ELSE 0 END) AS BarCount
FROM
    `mytable`