Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 4)
    ExpressionList (children 1)
     Asterisk
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test1
    Function greater (children 1)
     ExpressionList (children 2)
      Identifier a
      Literal UInt64_10
    Set
