Merge pull request #12 from Meg528/patch-4

Update 2-sql-vs-aggregation.mdx

docs/20-what-is-aggregation/2-sql-vs-aggregation.mdx

@@ -1,14 +1,14 @@
 ---
-description: Let's compare SQL with an Aggregation Pipeline 
+description: Let's compare SQL with an aggregation pipeline. 
 ---
 
 # 📘 SQL vs Aggregations
 
 ## SQL
 
-A SQL query statement usually starts with a `SELECT` where we put a list of the fields we need, then a `FROM` clause to state the table/s (or as in this case the subquery) that will return the rows. We can filter out using `WHERE` and group data using `GROUP`.
+A SQL query statement usually starts with a `SELECT` where we put a list of the fields we need, then a `FROM` clause to state the table/s (or in this case, the subquery) that will return the rows. We can filter out using `WHERE` and group data using `GROUP`.
 
-We read this from the inside. If there's too much nesting is not easy to follow.
+We read this from the inside. If there's too much nesting, it's not easy to follow.
 
 ```SQL
 SELECT
@@ -33,9 +33,9 @@ FROM (
 GROUP BY city;
 ```
 
-## Equivalent MongoDB Aggregation Pipeline
+## Equivalent MongoDB aggregation pipeline
 
-Here we pass three stages, one to return one document per element in the `address` array, then we filter out to get only the documents that have a `home` address location and finally we do the grouping. As we'll see, this can be split and tested separately, and resembles our code. 
+Here we pass three stages: one to return one document per element in the `address` array, and then we filter out to get only the documents that have a `home` address location. Finally, we do the grouping. As we'll see, this can be split and tested separately and resembles our code. 
 
 ```js
 db.customers.aggregate([
@@ -59,4 +59,4 @@ db.customers.aggregate([
 
 :::info
 See also [SQL to Aggregation Mapping Chart](https://www.mongodb.com/docs/manual/reference/sql-aggregation-comparison/)
-:::
+:::