Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Function count (children 1)
      ExpressionList
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier t_constraints_where
    Function or (children 1)
     ExpressionList (children 2)
      Function greater (children 1)
       ExpressionList (children 2)
        Identifier b
        Literal UInt64_20
      Function less (children 1)
       ExpressionList (children 2)
        Identifier b
        Literal UInt64_8