ASP.Net MVC converting Sql to Linq - linq

Question

I'm updating an old app, to use EF and Linq. I'm having trouble with one of the queries - in SQL it is:
SELECT id, type_id, rule_name, rule_start, rule_end, rule_min
FROM Rules
WHERE (rule_min > 0)
AND (rule_active = 1)
AND (rule_fri = 1)
AND ('2012-01-01' BETWEEN rule_start AND rule_end)
AND (id IN
(SELECT rule_id
FROM RulesApply
WHERE (type_id = 3059)))
ORDER BY pri
So far I have:
var rules = db.Rules.Include("RulesApply")
.Where(t => (t.rule_active == 1)
&& (t.rule_min > 0)
&& (dteFrom >= t.rule_start && dteFrom <= t.rule_end)
&& (this is where I'm stuck)
)
.OrderBy(r => r.pri);
It's the last subquery I'm stuck with adding into the LINQ above:
AND (id IN
(SELECT rule_id
FROM RulesApply
WHERE (type_id = 3059)))
Models are:
public class Rule
{
[Key]
public Int64 id { get; set; }
public Int64 hotel_id { get; set; }
public byte rule_active { get; set; }
public DateTime rule_start { get; set; }
public DateTime rule_end { get; set; }
public int rule_min { get; set; }
public int pri { get; set; }
public virtual ICollection<RuleApply> RulesApply { get; set; }
}
public class RuleApply
{
[Key, Column(Order = 0)]
public Int64 type_id { get; set; }
[Key, Column(Order = 1)]
public Int64 rule_id { get; set; }
[ForeignKey("rule_id")]
public virtual Rule Rule { get; set; }
}
Can anyone please help me complete this query?
Thank you,
Mark

Answer 1

Try doing this:
var rules = db.Rules.Include("RulesApply")
.Where(t => (t.rule_active == 1)
&& (t.rule_min > 0)
&& (dteFrom >= t.rule_start && dteFrom <= t.rule_end)
&& t.RulesApply.Any(a => a.type_id == 3059)
.OrderBy(r => r.pri);
If t.RulesApply is illegal (i.e. doesn't compile), then replace it with the correct reference to the navigation property found on your Rules object that points to the RulesApply object.

Answer 2

If you have set up navigational properties between the entities, you can navigate from one to the other:
//This gets the RulesApply object
var rulesapply = db.RulesApply.Single(x=> x.type_id == 3059);
//This gets all Rules connected to the rulesapply object through its navigational property
var rules = rulesapply.Rules;
//You can use LINQ to further refine what you want
rules = rules.Where( x=> /* and so on...*/ );
You can stack these statements together on a single line, I only split them up for readability purposes :)