What does the @ character do in SQL?

Question

I looked through the questions and noticed this:

SELECT prodid, issue FROM Sales WHERE custid = @custid AND datesold = SELECT MAX(datesold) FROM Sales s WHERE s.prodid = Sales.prodid AND s.issue = Sales.issue AND s.custid = @custid 

I was wondering what the "@" does before custID? Is this just a way of referencing custID from a selected table?

Answer 1

@CustID means this is a parameter that you will specify in the code later. This is the best way to protect against SQL injection. Create your query using parameters, not concatenation of strings and variables. The database engine puts the value of the parameter in the place where the placeholder is located, and there is no zero probability for SQL injection.

Answer 2

@ is used as a prefix denoting the names of stored procedures and functional parameters, as well as the names of variables

Answer 3

So, would you set the @custID value inside this request to select, or before you execute the request?

Something like that?

 SET @custID = '1'; 

Answer 4

Its parameter that you need to determine. to prevent SQL Injection, you must pass all of your variables as parameters.

Answer 5

You can use MySQL syntax: ? Microsoft SQL @ match MySQL ?

Answer 6

What you're talking about is a way to write a parameterized query. '@' just means that it is a parameter. You can add a value for this parameter at runtime.

 eg: sqlcommand cmd = new sqlcommand(query,connection); cmd.parameters.add("@custid","1"); sqldatareader dr = cmd.executequery(); 

Answer 7

 publish data where stoloc = 'AB143' | [select prtnum where stoloc = @stoloc] 

Here's how @ works.

Answer 8

@ and then the number are the parameters in the order in which they are listed in the function.