Question

I currently have an SQL query which is currently called multiple times like this (pseudo code):

foreach(KeyValuePair kvp in someMapList)
{
    select col1 from table where col2 = kvp.key and col3 = kvp.value;
    //do some processing on the returned value
}

The above could obviously call the database a large number of times if it is a big list of pairs.

Can anyone think of a more efficient piece of SQL which could essentially return a list of specific values based on a list of two unique pieces of information so that the processing can be done in bulk? One obvious one would be to build up a big piece of SQL with ORs but this would probably be quite inefficient?

Thanks

Carl

Answer 1

Insert KeyValuePair into a table and use a JOIN man
or (if c#)

from record in table
join key in someMap on record.col2 equals key.key && record.col3 equals key.keyvalue
select col1 //or some anonymous type or a DTO I do not know...

That is WAY more efficeint:D