Add Grab A Random Record From The Database as a Rails til

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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-_1157 TILs and counting..._
+_1158 TILs and counting..._
 
 ---
 
@@ -705,6 +705,7 @@ _1157 TILs and counting..._
 - [Get An Empty ActiveRecord Relation](rails/get-an-empty-activerecord-relation.md)
 - [Get The Column Names For A Model](rails/get-the-column-names-for-a-model.md)
 - [Get The Current Time](rails/get-the-current-time.md)
+- [Grab A Random Record From The Database](rails/grab-a-random-record-from-the-database.md)
 - [Handle Named Arguments In A Rake Task](rails/handle-named-arguments-in-a-rake-task.md)
 - [Hash Slicing](rails/hash-slicing.md)
 - [Ignore Poltergeist JavaScript Errors](rails/ignore-poltergeist-javascript-errors.md)

rails/grab-a-random-record-from-the-database.md

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+# Grab A Random Record From The Database
+
+I recently learned of a clever way to grab a random record for a particular
+model from the database. This is handy if you are poking around in the database
+to see what some records look like.
+
+Order the records for that table randomly and then grab the first.
+
+```ruby
+Event.order('random()').first
+```
+
+This grabs a random `Event` record from the `events` table.
+
+Note, however, that for Rails 6+, this approach won't work. Because of some
+extra safety measures around executing raw SQL, you'll instead have to write
+the above as:
+
+```ruby
+Event.order( Arel.sql('random()') ).first
+```
+
+This uses
+[`Arel.sql`](https://api.rubyonrails.org/classes/Arel.html#method-c-sql) to
+mark `'random()'` as a known-safe string of SQL.
+
+Because we are explicitly passing a string that represents a known-safe
+function call, this is fine. Take care to not pass any user-generated SQL in a
+scenario like this unless you know what you're doing.
+
+[source](https://stackoverflow.com/a/49525874/535590)