Question

please consider this table:

PK_Id          Number            Year            Month             Value
-------------------------------------------------------------------------
 1              1                2000              5                 100000
 410            4                2000              6                 10000
 8888           1                2001              5                 100

I Id=8888 and now I want to first select record with Id=8888 and second select previos year of that record*(I mean Id=1)*. How I can do this with linq and one query.

basically we have some queries that first it should find a value from a table (that may be not PK) and find Corresponding records in another tables. How I can do this with linq and one reference to database.

thanks

Answer 1

from a in Record
where a.PK_Id == 8888
from b in Record
where b.Number == a.Number && b.Year == a.Year - 1
select new { Current = a, Previous = b }

or

Record
.Where(a => a.PK_Id == 888)
.SelectMany(a =>
    Record
    .Where(b => b.Number == a.Number && b.Year == a.Year - 1)
    .Select(b => new { Current = a, Previous = b })