InsertQuery   (children 3)
 Identifier alter_column
 ExpressionList (children 2)
  Identifier x
  Identifier y
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 2)
     Identifier number (alias x)
     Function negate (alias y) (children 1)
      ExpressionList (children 1)
       Identifier number
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier system.numbers
    Literal UInt64_50
