Linq2SQL “or/and” operators (ANDed / ORed conditions)

Question

Let\'s say we need to apply several conditions to select from a table called \"Things\" (unknown count and nature)

if conditions are known, we can write

Answer 1

For OR, you have two choices:

• use Union/Concat
• write the Expression in code

The second is closer to the .Where(x => {a} || {b}).

If you are using LINQ-to-SQL, you can use Expression.Invoke to combine multiple separate lambda expressions (see this answer) - however, this isn't supported in Entity Framework. In EF, you have to build the entire expression as a single block, using Expression.OrElse; for example here or here.