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Update active_record_querying.md

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Pablo Alonso 2024-04-05 23:59:53 +02:00 committed by GitHub
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guides/source/active_record_querying.md
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@ -2610,13 +2610,13 @@ Running EXPLAIN
You can run [`explain`][] on a relation. EXPLAIN output varies for each database.
For example, running
For example, running:
```ruby
Customer.where(id: 1).joins(:orders).explain
```
may yield
may yield this for MySQL and MariaDB:
```sql
EXPLAIN SELECT `customers`.* FROM `customers` INNER JOIN `orders` ON `orders`.`customer_id` = `customers`.`id` WHERE `customers`.`id` = 1
@ -2636,11 +2636,9 @@ EXPLAIN SELECT `customers`.* FROM `customers` INNER JOIN `orders` ON `orders`.`c
2 rows in set (0.00 sec)
```
under MySQL and MariaDB.
Active Record performs a pretty printing that emulates that of the
corresponding database shell. So, the same query running with the
PostgreSQL adapter would yield instead
PostgreSQL adapter would yield instead:
```sql
EXPLAIN SELECT "customers".* FROM "customers" INNER JOIN "orders" ON "orders"."customer_id" = "customers"."id" WHERE "customers"."id" = $1 [["id", 1]]
@ -2658,7 +2656,7 @@ EXPLAIN SELECT "customers".* FROM "customers" INNER JOIN "orders" ON "orders"."c
Eager loading may trigger more than one query under the hood, and some queries
may need the results of previous ones. Because of that, `explain` actually
executes the query, and then asks for the query plans. For example,
executes the query, and then asks for the query plans. For example, running:
```ruby
Customer.where(id: 1).includes(:orders).explain