docs: revise content

Signed-off-by: Wing-Kam Wong <wingkwong.code@gmail.com>

packages/noco-docs/content/en/index.md

@@ -28,10 +28,10 @@ Also NocoDB's app store allows you to build business workflows on views with com
 - ⚡  Search, sort, filter, hide columns with uber ease
 - ⚡  Create Views : Grid, Gallery, Form
 - ⚡  Share Views : public & password protected
-- ⚡  Personal & locked Views 
+- ⚡  Collaborative & locked Views 
-- ⚡  Upload images to cells (Works with S3, Minio, GCP, Azure, DigitalOcean, Linode, OVH, BackBlaze)!!
+- ⚡  Upload images to cells (Works with S3, Minio, GCP, Azure, DigitalOcean, Linode, OVH, BackBlaze)
-- ⚡  Roles : Owner, Creator, Editor, Commenter, Viewer, Commenter, Custom Roles.
+- ⚡  Roles : Owner, Creator, Editor, Commenter, Viewer
-- ⚡  Access Control : Fine-grained access control even at database, table & column level.
+- ⚡  Access Control : Fine-grained access control even at database, table & column level
 
 ### App Store for workflow automations
 - ⚡  Chat : Microsoft Teams, Slack, Discord, Mattermost
@@ -43,7 +43,7 @@ Also NocoDB's app store allows you to build business workflows on views with com
 ### Programmatic API access via
 - ⚡  REST APIs
 - ⚡  Includes JWT Authentication & Social Auth
-- ⚡  API tokens to integrate with Zapier, Integromat.
+- ⚡  API tokens to integrate with Zapier, Integromat
 
 ##  Why are we building this?
 Most internet businesses equip themselves with either spreadsheet or a database to solve their business needs. Spreadsheets are used by a Billion+ humans collaboratively every single day. However, we are way off working at similar speeds on databases which are way more powerful tools when it comes to computing. Attempts to solve this with SaaS offerings has meant horrible access controls, vendor lockin, data lockin, abrupt price changes & most importantly a glass ceiling on what's possible in future.

packages/noco-docs/content/en/setup-and-usages/column-operations.md

@@ -60,9 +60,4 @@ Filters allow you to restrict/organize your data on the view as per your needs.
 
 ### Supported filters
 
-Currently we support filter types - `is equal`, `is not equal`, `is like`, `is not like`, `is null`, `is not null` for string fields. We also support filter types - `>`, `<`, `>=`, and `<=` for numeric fields.
+Currently we support filter types - `is equal`, `is not equal`, `is like`, `is not like`, `is null`, `is not null` for string fields. We also support filter types - `>`, `<`, `>=`, and `<=` for numeric fields. Also we provide `is empty` and `is not empty` for checking if the column is empty or not.
-
-#### Demo
-
-<img src="https://github.com/dstala/nocodb-files/blob/2c4ca2ff31460ee5636262e88ba303e2d436ba54/ColumnFilter.gif?raw=true" width="100%"/>
-<!-- img src="https://media4.giphy.com/media/eap5WSJfa05Qk7F3gm/giphy.gif?cid=790b761142dbc95c4f86b23a57fb0a9cb261292a88908e06&rid=giphy.gif&ct=g" width="60%"/ -->

packages/noco-docs/content/en/setup-and-usages/formulas.md

@@ -56,9 +56,10 @@ menuTitle: "Formulas"
 | `*`      | `column1 * column2`     | Multiplication of numeric values |
 | `/`      | `column1 / column2`     | Division of numeric values       |
 
-> To change order of arithmetic operation, use round bracket parantheses `()`  
+<alert type="success">
-> Example: `(column1 + (column2 * column3) / (3 - column4 ))`
+Tip :To change the order of arithmetic operation, you can use round bracket parantheses (). <br/>
-
+Example: (column1 + (column2 * column3) / (3 - column4 ))
+</alert>
 
 ### String Functions
 

packages/noco-docs/content/en/setup-and-usages/primary-value.md

@@ -6,11 +6,11 @@ category: "Product"
 menuTitle: "Primary value"
 ---
 
-## What is a 'Primary value' ?
+## What is a `Primary Value` ?
 - Primary value as the name stands is the primary or main value within a row of a table that you generally associate that row with.
 - It should be usually associated with a column which is uniquely identifiable. However, this uniqueness is not enforced at the database level.
 
-## What is the use of 'Primary value' ?
+## What is the use of `Primary Value` ?
 - Within a spreadsheet, primary value are always highlighted so that it is easier to recognise what row we are in.
 - And when LinkToAnotherRecord is created between two tables - it is the primary value that appears in LinkToAnotheRecord column.