Mean Of @ symbol In Parameterized Query?

[AnagJohari]

I want to know the meaning of @ symbol In parameterized query.
apart from this if i write an query like this
Delete * From Client Where Id=@Id
Can u explain the work Of @Id?
its just like a variable in which we store the value & set in id or any diffrent thing.
thank you
or we can write @AnyName inplace of @Id while id is the column name in a database,

[Jim Doherty]

@AnagJohari
the @ is merely a set variable stating that the whatever is contained in @ (distinquished by the sequence of characters immediately following it) is to be understood as a parameter variable

stating this:

Delete * From Client Where Id=Id

will delete all records in your table

whereas
this:

Delete * From Client Where Id=@Id

will delete only those records that match the value contained in the variable @Id

You do not have to specifically use the term @Id it can be @Anyname or @ThisVariable or @MickeyMouse it really does not matter what you suffix @