SQL, where in usage

First of all we need to know where is what is: a character judgment . In SQL operation, the control select only the specified row.
in fact classified as special comparison operators
expr1 between expr2 and expr3: represents the value of expr1 and expr2 between expr3
expr1 in (expr2, expr3, expr4, ...) represents expr1 is equal to any back brace inside an expression values
like: string matching, like creating characters after the wildcard
is null: null value is equal to the specified requirements