>Hi everybody,
>
>I have the following code
>
>
> EnumerableRowCollection<DataRow> query;
> if (checkType && checkCategory)
> query = from c in dtMax4SaleLimits.AsEnumerable()
> where ((2 == c.Field<Byte>("type") && lsn_cat == c.Field<String>("lsn_cat"))
> || (3 == c.Field<Byte>("type") && lessontype == c.Field<Int32>("lessontype")))
> && (c.Field<DateTime?>("start_time") < ending_time &&
> c.Field<DateTime?>("end_time") > begin_time)
> select c;
> else
> {
> if (checkCategory)
> query = from c in dtMax4SaleLimits.AsEnumerable()
> where (2 == c.Field<Byte>("type") && lsn_cat == c.Field<String>("lsn_cat"))
> && (c.Field<DateTime?>("start_time") < ending_time &&
> c.Field<DateTime?>("end_time") > begin_time)
> select c;
> else
> query = from c in dtMax4SaleLimits.AsEnumerable()
> where (3 == c.Field<Byte>("type") && lessontype == c.Field<Int32>("lessontype"))
> && (c.Field<DateTime?>("start_time") < ending_time &&
> c.Field<DateTime?>("end_time") > begin_time)
> select c;
> }
>
> Int32 recordsCount = query.Count();
> if (0 == recordsCount)>
>This code in executed in the loop for 10 different time values. However, I noticed that the lesson type and lsn_cat is not matching, therefore every time I'll get 0 rows. So, I am thinking I may try to execute my query first for the conditions without time checks and if it returns 0 rows, there is no need for the loop at all.
>
>The question is - how should I proceed - should I use two separate query variables - one for the main query without the extra date condition and another with the condition or there is a way to re-use the same query variable and add extra where condition?
>
>Thanks in advance.
1) You can use the LINQ method syntax to add additional where clauses to your query, and if you want to, reuse the query variable.
2) If you are only checking if records exist, use the Any method.
