The @CustID means it's a parameter that you will supply a value for later in your code. This is the best way of protecting against SQL injection. Create your query using parameters, rather than concatenating strings and variables. The database engine puts the parameter value into where the placeholder is, and there is zero chance for SQL injection.
Omettere le stringhe di query con valore null Le query anonimizzate costituiscono spesso la query più comune di un sito. Una query anonimizzata viene riportata come stringa di lunghezza zero nella tabella. Se vuoi vedere la query più cercata per criteri specifici, probabilmente devi omettere i valori delle query di lunghezza zero dalla query SQL.
Querying relational databases requires SQL, which is the only language designed to communicate with them. As a matter of fact, how SQL is used distinguishes business intelligence tools from one ...
I have seen SQL that uses both != and <> for not equal. What is the preferred syntax and why? I like !=, because <> reminds me of Visual Basic.
Should I use != or <> for not equal in T-SQL? - Stack Overflow
In SQL, anything you evaluate / compute with NULL results into UNKNOWN This is why SELECT * FROM MyTable WHERE MyColumn != NULL or SELECT * FROM MyTable WHERE MyColumn <> NULL gives you 0 results.
sql - Not equal <> != operator on NULL - Stack Overflow
Microsoft SQL Server is one of the exceptions: it doesn't support , and requires .
The other answers are correct if you're dealing with SQL Server, and it's clear that you are. But since the question title just says SQL, I should mention that there are some forms of SQL such as MySQL where a pound sign is used as an alternative commenting symbol.