MySQL, get rows for non-matching reference or reference does not exist in other table

MySQL, select non-matching reference or reference does not exist in other table.

For example.

table: category
category_id,    category_name
1               XYZ_1
2               XYZ_2
3               XYZ_3
4               XYZ_4
5               XYZ_5
6               XYZ_6

table: type
type_id,    type_name
1           A
2           B
3           C
4           D

table: type_match
match_Id,   type_id category_id
1           2       1
2           3       1
3           4       1
4           1       1
5           2       2
6           3       2
7           2       3       
8           4       3
9           2       4

I need category_id where type_id is not 3 or category_id does not exist in type_match table:
expected result:

3  // category_id exist in type_match table but not matching type_id = 3
4  // category_id exist in type_match table but not matching type_id = 3
5  // category_id does not exist in type_match table
6  // category_id does not exist in type_match table

Please help.

How many types of film balance exist?

I’m collating some data about photographic films and their characteristics for a project I’m working on.

Right now I’m looking into film balance and I’ve come across two types, ‘Daylight‘ and ‘Tungsten‘.

Do any others exist?

And, is film balance only relevant to colour films?


what to do if an item already exist in Treeview tkinter

what do I need to do if an item already exist in Treeview tkinter and I don’t want to remove all two items?
I need help please.

c++ – Does there exist a type similar to std::string (i.e., holding blobs of data of arbitrary length) that does not use the null terminator?

I use std::string to hold arbitrary blobs of binary data. It works this way, but is slightly inefficient as it needs to add the null terminator to the end of the blob. (C++11 spec is that c_str() and data() are the same, and return a pointer to a blob with a null terminator at the end.) Is there a better type to use, that still supports common operations (copy constructor, assignment operator, etc)?

ERROR in src / app / services / auth.service.ts: 15: 21 – error TS2339: the property & # 39; auth & # 39; does not exist on type & # 39; AngularFireAuth & # 39;

I am creating an authentication project with ionic and firebase, but I encountered this error and I cannot resolve it. So far, the app only performs the registration and login methods.the auth property is in error.

Do there exist graphs whose adjacency matrix is ​​positive semi-definite?

If so, could you provide examples and specify the conditions under which this occurs? Thank you in advance

Does the discussion “console games vs PC” still exist?

As far as I can remember, I’ve observed as teenager an ongoing discussion in the 90s, if not even a flame war, between console and PC gamers.

  • For most, having both a PC and a gaming console was simply not affordable
  • Generally, PC games seemed to have larger variety of game genres and generally provide access to more complex games, but consoled seemed to offer more colorful and vivid experiences.
  • Some games where of course then ported between different platforms, some not.

Now I must admit I am almost out of the world of games since more than two decades.

Today, as far as I can see, really many games releases appear simultaneously for many platform.

My question:

  • Does the discussion still exist in the gaming community, I mean, if yes, what are non-opiniated hard facts in this discussion? (beyond simple taste preference)
  • Or if not can we state for example, consoles have become more or less very specialized PCs (or provide other facts based arguments that such debates have descreased)?

Please note: this is not the question about “which platform is better”.
It a yes/no question about factual existence of noticable debates on this topic.

php – Target class [DataTypesTableSeederCustom] does not exist

i use laravel6 and travel, i create a craft order for installation use next cmd php artisan make: command EcommerceInstall
, I copy DataTypesTableSeeder of database/seeder and I rename it by DataTypesTableSeederCustom, I am modifying my file that I wrote EcommerceInstall.php but it gives me an error class (DataTypesTableSeederCustom) does not exist.
i think i forgot to import the class but i don't know where.


public function handle()
        if ($this->confirm('this well delete all you current data and install the dummy default data, Are you sure ?')) {

                $copySuccess = File::copyDirectory(public_path('img/products'),public_path('storage/products/dummy'));
                    $this->info('images succefully copied to storage folder');
                $this->call('migrate:fresh', (
                    '--seed' => true,
                $this->call('db:seed', (
                    '--class' => 'DataTypesTableSeederCustom'

   $this->info('Dummy data installed');


troubleshooting – Why does my camera turn off every time I try to take a picture and when I do it why when I go to read it says the file does not exist

I just bought a camera and it is a Polaroid is048 and I bought a MicroSD card with it and I put batteries of new batteries and with the MicroSD card and each once i try to take a photo, it turns off or if it takes a photo but it does not appear in playback. And every time I charge it, it stays on for 5 minutes, then it loses all of its battery.

Camera model: Polaroid is048

google search console – How can I fix the indexed issue, although blocked by robots.txt if the reported pages do not exist at all?

I found related information like How to fix Google "Indexed, although blocked by robots.txt" but that doesn't answer my question.

The pages I saw in the report do not exist at all.

enter description of image here

For example, the two links above do not exist at all. I don't know why people add a number or a image?url= to my URL. He's so weird.

How can I tell Google to ignore these URLs?