Unity has a custom implementation of equality == operator (see Custom == operator, should we keep it? which often leads to confusion / unexpected behavior. Even if an UnityEngine.Object has a value equal to null it is sometimes not == null. Object rather still stores some meta data in it e.g. you get a MissingReferenceException, … Read more
There is absolutely no difference in functionality between is_null and === null. The only difference is that is_null is a function and thus is marginally slower (function call overhead) can be used as a callback, e.g. array_map(‘is_null’, $array). Personally, I use null === whenever I can, as it is more consistent with false === and … Read more
Since aa is the set/object that might be null, can you check aa == null ? (aa / xx might be interchangeable (a typo in the question); the original question talks about xx but only defines aa) i.e. select new { AssetID = x.AssetID, Status = aa == null ? (bool?)null : aa.Online; // a … Read more
This problem reported on Microsoft Connect reveals some differences between COALESCE and ISNULL: an early part of our processing rewrites COALESCE( expression1, expression2 ) as CASE WHEN expression1 IS NOT NULL THEN expression1 ELSE expression2 END. In [this example]: COALESCE ( ( SELECT Nullable FROM Demo WHERE SomeCol = 1 ), 1 ) we generate: … Read more
In MySQL, NULL is considered as a ‘missing, unknown value’, as opposed to no value. Take a look at this MySQL Reference on NULL. Any arithmetic comparison with NULL does not return true or false, but returns NULL instead., So, NULL != ‘C’ returns NULL, as opposed to returning true. Any arithmetic comparison with ‘NULL’ … Read more