Multiple WHERE Clauses with LINQ extension methods

by

Two ways:

results = results.Where(o => (o.OrderStatus == OrderStatus.Open) &&
                             (o.CustomerID == customerID));

or:

results = results.Where(o => (o.OrderStatus == OrderStatus.Open))
                 .Where(o => (o.CustomerID == customerID));

I usually prefer the latter. But it’s worth profiling the SQL server to check the query execution and see which one performs better for your data (if there’s any difference at all).

A note about chaining the .Where() methods: You can chain together all the LINQ methods you want. Methods like .Where() don’t actually execute against the database (yet). They defer execution until the actual results are calculated (such as with a .Count() or a .ToList()). So, as you chain together multiple methods (more calls to .Where(), maybe an .OrderBy() or something to that effect, etc.) they build up what’s called an expression tree. This entire tree is what gets executed against the data source when the time comes to evaluate it.

More Related Contents:

  1. How to display words that appear more than 'x' times in a text? [closed]
  2. Can’t use Count() in C#
  3. Retrieving Property name from lambda expression
  4. How do I apply OrderBy on an IQueryable using a string column name within a generic extension method?
  5. When to use BlockingCollection and when ConcurrentBag instead of List?
  6. How can I get every nth item from a List?
  7. How to get the index of an element in an IEnumerable?
  8. How do I invoke an extension method using reflection?
  9. Use LINQ to group a sequence of numbers with no gaps
  10. What is LINQ and what does it do? [closed]
  11. Find index of a value in an array
  12. LINQ: combining join and group by
  13. Add two Lists of different length in C#
  14. Deferred execution and eager evaluation
  15. Number of occurrences of a character in a string [duplicate]
  16. Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator
  17. Linq query built in foreach loop always takes parameter value from last iteration
  18. “The LINQ expression node type ‘Invoke’ is not supported in LINQ to Entities” – stumped!
  19. Rotate – Transposing a List using LINQ C#
  20. High memory consumption with Enumerable.Range?
  21. How to Get XML Node from XDocument
  22. How to await a list of tasks asynchronously using LINQ?
  23. Use linq to generate direct update without select
  24. How to create LINQ Query from string?
  25. Max return value if empty query
  26. Sort one list by another
  27. Get sum of two columns in one LINQ query
  28. Creating a LINQ select from multiple tables
  29. If Else in LINQ
  30. Parsing a string C# LINQ expression

Leave a Comment