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silverbullet/website/🔌 Directive/Query.md
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fix query grammar link (#159)
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Query

The #query is the most widely used directive. It can be used to query various data sources and render results in various ways.

Syntax

  1. start with: <!-- #query [QUERY GOES HERE] -->
  2. end with: <!-- /query -->
  3. write your query: replace [QUERY GOES HERE] with any query you want using the options below.
  4. available query options: Usage of options is similar to SQL except for thespecial render option. The render option is used to display the data in a format that you created in a separate template.
    • where
    • order by
    • limit
    • select
    • render

P.S.: If you are a developer or have a technical knowledge to read a code and would like to know more about syntax, please check out query grammar.

2.1. Available query operators:

  • = equals
  • != not equals
  • < less than
  • <= less than or equals
  • > greater than
  • >= greater than or equals
  • =~ to match against a regular expression
  • !=~ does not match this regular expression
  • in member of a list (e.g. prop in ["foo", "bar"])

Further, you can combine multiple of these with and. Example prop =~ /something/ and prop != “something”.

3. How to run a query?

After writing the query, there are three options:

  1. Open the command palette and run {[Directives: Update]}
  2. Use shortcut: hit Alt-q (Windows, Linux) or Option-q (Mac)
  3. Go to another page and come back to the page where the query is located, it always updates when a page is loaded

After using one of the options, the “body” of the query is replaced with the new results of the query data will be displayed.

4. Data sources

Available data sources can be categorized as:

  1. Builtin data sources
  2. Data that can be inserted by users
  3. Plug’s data sources

The best part about data sources: there is auto-completion. 🎉

Start writing <!— #query or simply use /query slash command, it will show you all available data sources. 🤯

4.1. Available data sources

  • page: list of all pages
  • task: list of all tasks created with [ ]
  • full-text: use it with where phrase = "SOME_TEXT". List of all pages where SOME_TEXT is mentioned
  • item: list of ordered and unordered items such as bulleted lists
  • tag: list of all hashtags used in all pages
  • link: list of all pages giving a link to the page where query is written
  • data: You can insert data using the syntax below. You can query the data using the data source.
name: John
age: 50
city: Milan
country: Italy
---
name: Jane
age: 53
city: Rome
country: Italy
---
name: Francesco
age: 28
city: Berlin
country: Germany

Example:

name age city country page pos
John 50 Milan Italy 🔌 Directive/Query 0
Jane 53 Rome Italy 🔌 Directive/Query 1

4.2 Plugs’ data sources

Certain plugs can also provide special data sources to query specific data. Some examples are:

  • 🔌 Github provides gh-pull to query PRs for selected repo
  • 🔌 Mattermost provides mm-saved to fetch (by default 15) saved posts in Mattermost

For a complete list of data sources, please check plugs’ own pages.

5. Templates

Templates are predefined formats to render the body of the query.

5.1 How to create a template?

It is pretty easy. You just need to create a new page. However, it is recommended to create your templates using template/[TEMPLATE_NAME] convention. For this guide, we will create template/plug to display list of Plugs available in Silver Bullet. We will use this template in the Examples section below.

5.2 What is the syntax?

We are using Handlebars which is a simple templating language. It is using double curly braces and the name of the parameter to be injected. For our template/plug, we are using simple template like below.

* [[{{name}}]] by **{{author}}** ([repo]({{repo}}))

Let me break it down for you

  • * is creating a bullet point for each item in Silver Bullet
  • [[{{name}}]] is injecting the name of Plug and creating an internal link to the page of the Plug
  • **{{author}}** is injecting the author of the Plug and making it bold
  • ([repo]({{repo}})) is injecting the name of the Plug and creating an external link to the GitHub page of the Plug

For more information on the Handlebars syntax, you can read the official documentation.

5.3 How to use the template?

You just need to add the render keyword followed by the link of the template to the query like below:

<!-- #query page where type = "plug" render [[template/plug]] -->
<!-- /query-->

#query page where type = "plug" render [[template/plug]]

You can see the usage of our template in example 6.4 below.

6. Examples

We will walk you through a set of examples starting from a very basic one through one formatting the data using templates.

Our goal in this exercise is to (i) get all plug pages (ii) ordered by last modified time and (iii) display in a nice format.

For the sake of simplicity, we will use the page data source and limit the results not to spoil the page.

6.1 Simple query without any condition

Goal: We would like to get the list of all pages.

Result: Look at the data. This is more than we need. The query even gives us template pages. Let's try to limit it in the next step.

name lastModified contentType size perm type uri repo author
Markdown 1669534332564 text/markdown 1022 rw
🔌 Graph View 1669388320673 text/markdown 1042 rw plug github:bbroeksema/silverbullet-graphview/graphview.plug.json https://github.com/bbroeksema/silverbullet-graphview Bertjan Broeksema
SETTINGS 1667053645895 text/markdown 169 rw

6.2 Simple query with a condition

Goal: We would like to get all plug pages sorted by last modified time.

Result: Okay, this is what we wanted but there is also information such as perm, type and lastModified that we don't need.

name lastModified contentType size perm type repo share-support
🔌 Collab 1669545776517 text/markdown 2926 rw plug https://github.com/silverbulletmd/silverbullet true
🔌 Tasks 1669536555227 text/markdown 1231 rw plug https://github.com/silverbulletmd/silverbullet
🔌 Share 1669536545411 text/markdown 672 rw plug https://github.com/silverbulletmd/silverbullet
🔌 Markdown 1669536539800 text/markdown 268 rw plug https://github.com/silverbulletmd/silverbullet true
🔌 Emoji 1669536531680 text/markdown 155 rw plug https://github.com/silverbulletmd/silverbullet

6.3 Query to select only certain fields

Goal: We would like to get all plug pages, selecting only name, author and repo columns and then sort by last modified time.

Result: Okay, this is much better. However, I believe this needs a touch from a visual perspective.

|name |author|repo |ri| |-----------||----------------------------------------------|| |🔌 Collab ||https://github.com/silverbulletmd/silverbullet|| |🔌 Tasks ||https://github.com/silverbulletmd/silverbullet|| |🔌 Share ||https://github.com/silverbulletmd/silverbullet|| |🔌 Markdown||https://github.com/silverbulletmd/silverbullet|| |🔌 Emoji ||https://github.com/silverbulletmd/silverbullet||

6.4 Display the data in a format defined by a template

Goal: We would like to display the data from step 5.3 in a nice format using bullet points with links to Plug pages, with the author name and a link to their GitHub repo.

Result: Here you go. This is the result we would like to achieve 🎉. Did you see how I used render and template/plug in a query? 🚀

PS: You don't need to select only certain fields to use templates. Templates are smart enough to get only the information needed to render the data. Therefore, the following queries are the same in terms of end result when using the templates.

<!-- #query page select name author repo uri where type = "plug" order by lastModified desc limit 5 render [[template/plug]] -->

and:

<!-- #query page where type = "plug" order by lastModified desc limit 5 render [[template/plug]] -->