CreateQuery table_a (children 3)
 Identifier table_a
 Columns definition (children 1)
  ExpressionList (children 3)
   ColumnDeclaration event_id (children 1)
    DataType UInt64
   ColumnDeclaration something (children 1)
    DataType String
   ColumnDeclaration other (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType String
 Storage definition (children 2)
  Function MergeTree
  Identifier event_id
