This is because it is converting the email field (which I assume is a varchar field) to an integer. Any field without a valid integer will equate to 0. You should make sure that you only compare string fields to string values (same goes for dates, comparing to dates). The query should be as follows. … Read more
Nope, I’m afraid not. The only things you can do with constraints are: where T : class – T must be a reference type where T : struct – T must be a non-nullable value type where T : SomeClass – T must be SomeClass or derive from it where T : ISomeInterface – T … Read more
You can write an extension method public static class MyExtensions { public static object GetProperty<T>(this T obj, string name) where T : class { Type t = typeof(T); return t.GetProperty(name).GetValue(obj, null); } } and use it like this var x = myList.Where(f => f.GetProperty(“Title”) == myValue);
The typical way to break up OR predicates is with UNION. Note that your example doesn’t fit well with your indexes. Even if you omitted field1 from the predicate, you’d have field2 >= 1000 OR field3 >= 2000, which can’t use an index. If you had indexes on (field1, field2) and (field1,field3) or field2 or … Read more
var query = someList.Where(a => (someCondition)? a == “something” : true); so, if ‘someCondition’ is false, ‘Where’ will be skipped.
The FindAll method of the List<T> class actually constructs a new list object, and adds results to it. The Where extension method for IEnumerable<T> will simply iterate over an existing list and yield an enumeration of the matching results without creating or adding anything (other than the enumerator itself.) Given a small set, the two … Read more
Judging from your output it looks like you have defined START_DATE as a timestamp. If it were a regular date Oracle would be able to handle the implicit conversion. But as it isn’t you need to explicitly cast those strings to be dates. SQL> alter session set nls_date_format=”dd-mon-yyyy hh24:mi:ss” 2 / Session altered. SQL> SQL> … Read more
1: The problem in the example f :: State s a f = State $ \x -> y where y = … x … is the parameter x. Things in the where clause can refer only to the parameters of the function f (there are none) and things in outer scopes. 2: To use a … Read more
Where finds items that match and only returns those that do (filtering). -> IEnumerable<A> in, IEnumerable<A> out Select returns something for all items in the source (projection / transformation). That something might be the items themselves, but are more usually a projection of some sort. -> IEnumerable<A> in, IEnumerable<B> out
Try this: SELECT * FROM MY_TABLE WHERE @parameter IS NULL OR NAME = @parameter;