A, joint table query
There must be at least two tables (except the table itself join itself, autolink query), and there is a relationship between two tables. For example, you can create two tables: article table and author table.
Article table:
| id | A primary key |
|---|---|
| Article_name | Article name, vARCHar (50), not null |
| Author_id | Author ID, int, not null |
Author table:
| id | A primary key |
|---|---|
| Author_name | Author name, varchar(20), not null |
1.1 Creating a Migration File
php artisan make:migration create_article_table php artisan make:migration create_author_table 
articleAdd field:
$table->increments('id');
$table->string('article_name'.50)->comment('Article Title');
$table->integer('author_id') -> comment('the author id');
$table->timestamps();
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Author + field:
$table->increments('id');
$table->string('author_name'.20) -> comment('Author name');
$table->timestamps();
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1.2 Migrating Files
Then perform the migration file:php artisan migrate 
1.3 Simulated data (through filler)
1. Create a fill file (can write multiple data table writes together)php artisan make:seeder ArticleAndAuthorTableSeeder 
php artisan db:seed --class=ArticleAndAuthorTableSeeder 
1.4 Example for querying a union table
Request to query the data table (article table, author table), query the information of the article contains the name of the author, a joint table query has a total: inner table, left table, right table.
SQL > select * from left;
select article.id,article.article_name, author.author_name from article left join author on article.author_id = author.id
Change the above SQL statement to a chained operation:
Syntax: DB facade/model -> join join table mode name (associated table name, table 1 field, operator, table 2 field)
Left link: If you want to executeThe left linkRather thanIn the linkYou can useleftJoinMethod, the method andjoinMethod to create a route:
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