CreateQuery nullable_alter (children 3)
 Identifier nullable_alter
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration d (children 2)
    DataType Date
    Literal \'2000-01-01\'
   ColumnDeclaration x (children 1)
    DataType String
 Storage definition (children 1)
  Function MergeTree (children 1)
   ExpressionList (children 3)
    Identifier d
    Identifier d
    Literal UInt64_1