public static StringExpression left(Expression<String> lhs, int rhs) {
        return left(lhs, ConstantImpl.create(rhs));
    }
Get the rhs leftmost characters of lhs

@param lhs string
@param rhs character amount
@return rhs leftmost characters
querydsl-sql/src/main/java/com/querydsl/sql/SQLExpressions.java