This is the kind of query that EF generates when it knows for sure that the query won’t return any results. Such a query minimizes database processing. How can EF be so sure? This can only be when for all it knows UserId in the database is not nullable. This, in turn, can only be … Read more
About null ‘anything’ NOT LIKE null yields null, not true. And only true qualifies for filter expressions in a WHERE clause. Most functions return null on null input (there are exceptions). That’s the nature of null in any proper RDBMS. If you desire a single expression, you could use: AND (column_default LIKE ‘nextval%’) IS NOT … Read more
null values represents “no value” or “nothing”, it’s not even an empty string or zero. It can be used to represent that nothing useful exists. NaN stands for “Not a Number”, it’s usually the result of a mathematical operation that doesn’t make sense, e.g. 0.0/0.0. One possible way to handle null values is to remove … Read more
Ordered comparison between a pointer and an integer is ill-formed in C++ (even when the integer is a null pointer constant such as it is in this case). The risk is that compilers are allowed to, and do, refuse to compile such code. You can rewrite it as either of these: if(myPtr != nullptr) if(myPtr)
Check Ick’s maybe. You don’t need to significantly refactor your code, just intersperse maybe proxies when necessary: params[:subject].maybe[:name] The same author (raganwald) also wrote andand, with the same idea.
A string is not an integer; and a blank string is not None or NULL. What you need to do is catch those instances where the field is blank and then cast it to None. foo = “something” # “something” is coming from your CSV file try: val = int(foo) except ValueError: # foo is … Read more
IS NULL and IS NOT NULL work for complex types too, so these two should be appropriate: select * from bla where recipient is not null select * from bla where recipient is null
\x00 That is a null char.
You could: SELECT COALESCE(SUM(columnA), 0) FROM my_table WHERE columnB = 1 INTO res; This happens to work, because your query has an aggregate function and consequently always returns a row, even if nothing is found in the underlying table. Plain queries without aggregate would return no row in such a case. COALESCE would never be … Read more
From your code, it looks like provider is a variant or some other variable, and not an object. Is Nothing is for objects only, yet later you say it’s a value that should either be NULL or NOT NULL, which would be handled by IsNull. Try using: If Not IsNull(provider) Then url = url & … Read more