CreateQuery t1 (children 3)
 Identifier t1
 Columns definition (children 1)
  ExpressionList (children 4)
   ColumnDeclaration key (children 1)
    DataType UInt64
   ColumnDeclaration a (children 1)
    DataType UInt8
   ColumnDeclaration b (children 1)
    DataType String
   ColumnDeclaration c (children 1)
    DataType Float64
 Storage definition (children 2)
  Function MergeTree (children 1)
   ExpressionList
  Identifier key