SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier bf_ngrambf_map_keys_test
   Function notEquals (children 1)
    ExpressionList (children 2)
     Function arrayElement (children 1)
      ExpressionList (children 2)
       Identifier map
       Literal \'K3\'
     Literal \'\'
