Question

The proper syntax in Linq for this SQL query is eluding me. I’d appreciate any hand with this.

SQL:

SELECT TOP 1 posdate 
FROM   dailypos 
GROUP  BY posdate 
HAVING Count(DISTINCT customernumber) = 3 
ORDER  BY posdate DESC) 

Essentially, I get files from 3 different customers and I need a quick way to determine the most recent date for which I have data from all 3. I’m open to a different approach, but this SQL works for what I need.

I can do the group, but I don’t know how to handle the 4th line (HAVING Count(Distinct…))

Thanks in advance.

Answer 1

Try something like this:

var result = context.dailypos
    .GroupBy(x => x.posdate)
    .Where(g => g.Select(x => x.customernumber).Distinct().Count() == 3)
    .Select(g => g.Key)
    .OrderByDescending(x => x)
    .Take(1);