// ColumnDeclaredType returns the declared type of the table column of a particular result column in SELECT statement. If the result column is an expression or subquery, then a NULL pointer is returned.
// ColumnDeclaredType returns the declared type of the table column of a particular result column in SELECT statement.
// If the result column is an expression or subquery, then a NULL pointer is returned.
// The left-most column is column 0.
// (See http://www.sqlite.org/c3ref/column_decltype.html)