From 29b1576b19a30c35f2c253f1d79f25de28d90f70 Mon Sep 17 00:00:00 2001
From: WinPooh32 <winpooh32@yandex.ru>
Date: Mon, 8 Jan 2024 17:03:33 +1000
Subject: [PATCH] Add aggregation section

---
 README.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/README.md b/README.md
index e6cb234..2a25ff1 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,21 @@ It does:
 - [SQL](https://pkg.go.dev/github.com/WinPooh32/norm/driver/sql)
 - MongoDB (TODO)
 
+## Aggregation
+
+For using in-memory aggregation functions model type must implement this interface:
+
+```go
+type Keyer[K comparable] interface {
+    Key() K
+}
+```
+
+Available functions:
+
+- [Lookup](https://pkg.go.dev/github.com/WinPooh32/norm#Lookup) - left outer join
+- [Group](https://pkg.go.dev/github.com/WinPooh32/norm#Group) - values grouping
+
 ## Examples
 
 ### SQL