Document sql.random (#836)

Author: ephys

docs/querying/raw-queries.mdx

@@ -4,6 +4,7 @@ title: Raw SQL (literals)
 ---
 
 import UuidSupportTable from '../_fragments/_uuid-support-table.mdx';
+import { DialectTableFilter } from '@site/src/components/dialect-table-filter.tsx';
 
 We believe that ORMs are inherently leaky abstractions. They are a compromise between the flexibility of SQL and the convenience of an object-oriented programming language.
 As such, it does not make sense to try to provide a 100% complete abstraction over SQL (which could easily be more difficult to read than the SQL itself).
@@ -541,6 +542,39 @@ These functions are supported by the following dialects:
 
 <UuidSupportTable />
 
+### `sql.random`
+
+`sql.random` generates a random float between 0 and 1, using the dialect-specific function to do so.
+
+```ts
+await sequelize.query(sql`INSERT INTO lottery (ticket) VALUES (${sql.random()})`);
+```
+
+The SQL generated by `sql.random()` varies by dialect:
+
+<DialectTableFilter>
+
+| PostgreSQL | MariaDB  | MySQL    | MSSQL    | SQLite                                                          | Snowflake  | db2      | ibmi     | Oracle                |
+| ---------- | -------- | -------- | -------- | --------------------------------------------------------------- | ---------- | -------- | -------- | --------------------- |
+| `RANDOM()` | `RAND()` | `RAND()` | `RAND()` | `((RANDOM() + 9223372036854775808.0) / 18446744073709551616.0)` | `RANDOM()` | `RAND()` | `RAND()` | `DBMS_RANDOM.VALUE()` |
+
+</DialectTableFilter>
+
+:::note About SQLite
+
+SQLite's native `RANDOM()` function returns a random integer in the range of a 64-bit signed integer. Sequelize normalizes this to a float between 0 and 1.
+
+If you want to use the native `RANDOM()` function in SQLite, you can use [`sql`](#writing-raw-sql).
+
+:::
+
+:::note About MSSQL
+
+Using `sql.random()` in an `ORDER BY` clause is a common way to get random ordering,
+however in MSSQL, it is better to use `NEWID()` for this purpose, as `RAND()` is evaluated only once per query, and will not give you random ordering.
+
+:::
+
 ### `sql.col`
 
 :::caution