Laravel：如何查询表，从每个唯一 item_id 的列中获取第一个值并将其分配给另一个表列

Question

I am completely new to Laravel and migrations in general.

I have 2 tables: claim_items and claims .

The table claim_items has 2 columns:

1. claim_id and refers to the id of the table claim (1 claim might have 1 or more claim items, while 1 or multiple claim items have only 1 claim)
2. claim_type .

The table claims has many columns among which:

1. id (of course)
2. claim_items_type

I need to write a migration that will query claim_items table, and for each claim_id (for each claim) it takes the first value of claim_type and assign that value to the column claim_items_type in the table claims (so that each claim has a column claim_items_type with the first value found from claim_items table relative to correspondent claim_id).

I tried lots of variation and I ended up messing everything and confusing myself more than before.

Any idea on how could I achieve this?

Answer 1

As Gert B explained, this looks like a custom command and you should be putting this under your controller. The migration file would simply contain create table and drop table commands in laravel language and is useful only for creating database table structure. There is absolutely nothing with respect to data in it. Further, if you want to insert/update the database with custom data, you should either go for seeder (that would update something like test data in your database) or you should be writing your custom controller which would do this job for you.

Suggestion would be

• Update your claim_items using direct SQL insert or migration file.
• Write a custom controller and user first() to grab the first occurrence of the result.

$conditions['column_name'] = 'Your required value';
$answer = DB::table('claim-item')->where($conditions)->first();

You may use this under a loop to get closer to your requirement.