where-clause

I have a recursive query which executes very fast if the WHERE clause contains a constant but becomes very slow if I replace the constant with a parameter having the same value. Query #1 - with constant ;WITH Hierarchy (Id, ParentId, Data, Depth) AS ( SELECT Id, ParentId, NULL AS Data, 0 AS Depth FROM Test UNION ALL SELECT h.Id, t.ParentId, COALESCE(h.Data, t.Data), Depth + 1 AS Depth FROM Hierarchy h INNER JOIN Test t ON t.Id = h.ParentId ) SELECT * FROM Hierarchy WHERE Id = 69 Query #2 - with parameter DECLARE @Id INT SELECT @Id = 69 ;WITH Hierarchy (Id, ParentId, Data, Depth) AS ( SELECT Id

I'm using linq to entities(EF). I have a constructor which takes 4 string parameters. Depending on what parameter is not null I have to build the linq query. I can do with if else statements but i also has other constructor with 10 parameters in that case there will be many combinations to check. Example: Constructor(p1,p2,p3,p4) { var prod= from p in ctxt.products.expand("items\details") where p.x==p1 && p.xx==p2 && p.xxx==p3 && p.xxxx==p4 select p; } In the above where clause there should be condition checks only if the parameter is not null. ie., if p2 is null then the where clause should

I need to create a query which checks if a field (string) contains one or more words supplied at run time. Basically I need to be able to ask a WhereOr question. This seems like it should be a common issue when dealing with LinqToSql. I found the following reference but can't make sense out of it - and have no idea how to use it in my project. i've tried the following loop: var query = from d in context.Domains select d; for (int i = 0; i < words.Length; i++) { query = query.Where(d => d.Name.Contains(words[i])); } but this builds a SQL query with WHERE AND Clauses NOT Where OR I use

I have a query that looks something like that: SELECT a, b, c, (SELECT d from B limit 0,1) as d FROM A WHERE d >= 10 I get the result that I want when I run the query without the where clause but when I add the where clause the query fails. Does anyone have a suggestion how to solve that? You can't use a column alias in WHERE clause. So you either wrap your query in an outer select and apply your condition there SELECT * FROM ( SELECT a, b, c, (SELECT d FROM B LIMIT 0,1) d FROM A ) q WHERE d >= 10 or you can introduce that condition in HAVING clause instead SELECT a, b, c, (SELECT d FROM B