Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 4)
    ExpressionList (children 2)
     Function toDate (children 1)
      ExpressionList (children 1)
       Identifier timestamp
     Function count (alias s) (children 1)
      ExpressionList
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
    ExpressionList (children 1)
     Function toDate (children 1)
      ExpressionList (children 1)
       Identifier timestamp
    Set