CreateQuery alter_column (children 3)
 Identifier alter_column
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration x (children 1)
    DataType UInt32
   ColumnDeclaration y (children 1)
    DataType Int32
 Storage definition (children 3)
  Function MergeTree
  Identifier x
  Identifier x
