CreateQuery test (children 3)
 Identifier test
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration a (children 1)
    DataType UInt8
   ColumnDeclaration b (children 1)
    DataType UInt8
 Storage definition (children 3)
  Function MergeTree
  Function tuple (children 1)
   ExpressionList (children 2)
    Identifier a
    Identifier b
  Set
