CreateQuery check_system_tables (children 3)
 Identifier check_system_tables
 Columns definition (children 1)
  ExpressionList (children 3)
   ColumnDeclaration Event (children 1)
    DataType Date
   ColumnDeclaration UserId (children 1)
    DataType UInt32
   ColumnDeclaration Counter (children 1)
    DataType UInt32
 Storage definition (children 1)
  Function MergeTree (children 1)
   ExpressionList (children 4)
    Identifier Event
    Function intHash32 (children 1)
     ExpressionList (children 1)
      Identifier UserId
    Function tuple (children 1)
     ExpressionList (children 3)
      Identifier Counter
      Identifier Event
      Function intHash32 (children 1)
       ExpressionList (children 1)
        Identifier UserId
    Literal UInt64_8192
