# An Introduction to [[dataview|Dataview]]
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This is a reformatted, web-compatible version of the very first [[Obsidian Community Talks|Obsidian Community Talk]], an overview of the [[dataview|Dataview]] plugin, held by [[SkepticMystic]].
The original slides can be found [[An Introduction to Dataview Slides|here]] and are best viewed with Obsidian and the [[obsidian-advanced-slides|Advanced Slides]] plugin or converted to [[revealjs]] with [[YT - Pandoc and Obsidian - Create slideshows, PDFs and Word documents|Pandoc]]. Make sure to also take a look at the [[YT - An Introduction to Dataview|YouTube video]] for in-depth explanations.
By [[SkepticMystic]]
## Overview
1. [[An Introduction to Dataview#Introduction|Broad Intro to Dataview]]
2. [[An Introduction to Dataview#Metadata|Metadata]]
3. [[An Introduction to Dataview#Dataview Queries|Dataview Queries]]
- [[An Introduction to Dataview#List|List]]
- [[An Introduction to Dataview#From|From]]
- [[An Introduction to Dataview#Where|Where]]
- [[An Introduction to Dataview#Task|Task]]
- [[An Introduction to Dataview#Table|Table]]
- [[An Introduction to Dataview#Sort|Sort]]
- [[An Introduction to Dataview#Flatten|Flatten]]
- [[An Introduction to Dataview#Group by|Group by]]
## Introduction
[[dataview|Dataview]] is a plugin which lets you query data from your vault. The *official documentation* which you can use for reference is available here:
https://blacksmithgu.github.io/obsidian-dataview
## Metadata
### What is it?
Metadata provides information _about_ your data.
It is _extra_ info that is either already _inherent_ in your data, or info that you **manually add**.
### Examples of Metadata 💡
#### Photographs
- Date & time ⏰
- Location 🌍
- People 🧑🤝🧑
My display picture has the following _inherent_ metadata:
But it could also be given other properties:
#### Markdown Notes
We can also add metadata to **Markdown notes** using a language called <abbr title="Yaml Ain't Markup Language"><em>YAML</em></abbr>.
- YAML is a **structured** way of adding _arbitrary_ metadata to a file.
### Adding YAML Metadata
1. At the **top** of your note, add 3 dashes `---`
2. Underneath that, you can start adding key-value pairs in the form `key: value`
3. To finish the metadata block, close it off with 3 dashes again `---`.
In the photo example, this would look as follows:
```yaml
---
dimensions: 1200x1200
bit depth: 24
title: "Mandala Display Picture"
rating: 5
---
```
#### YAML Lists
You can add more than one `value` to each `key` using _lists_.
There are two notations you can use:
##### 1. Inline
```yaml
foods: [apples, pears, oranges]
```
##### 2. Indented
```yaml
foods:
- apples
- pears
- oranges
```
**Note the spacing!**
### Types of Metadata
You can find this information on the [Dataview reference page](https://blacksmithgu.github.io/obsidian-dataview/#/README).
```yaml
number: 3.6
string: "Foo all the bars"
list:
- 1
- -2
- 3.5
- 1.61803
date:
- 2021-04
- "2021-04-09"
- 2021-04-09T12:12:54
link: [[2021-04-09 Daily Note]]
```
### Implicit Metadata in all notes
| Property | Value | Type |
| ------------ | ---------------------------------------- | -------- |
| `file.name` | File **title** | `string` |
| `file.path` | Full file **path** | `string` |
| `file.link` | **Link** to the file | `link` |
| `file.size` | **Size** (in bytes) of the file | `number` |
| `file.ctime` | Date that the file was **created** | `date` |
| `file.mtime` | Date that the file was last **modified** | `date` |
| `file.day` | The **date** contained in the note title | `date` |
| `file.tags` | An `array` of all **tags** in the note. | `array` |
Subtags are broken down by each level, so `#Tag/1/A` will be stored in the array as `[#Tag, #Tag/1, #Tag/1/A]`
## Dataview Queries
### `List`
Creates a _list_ of the specified notes
```dataview
list
```
### `From`
Determines **where** to get notes _from_.
#### From \#Tag
You can get all notes _from_ a specified **tag**:
```dataview
list
from #MOC
```
#### From "Folder"
All notes from a **folder**:
```dataview
list
from "1. Projects"
```
#### From \[\[Links\]\]
And even all notes with links coming _into_ a note:
```dataview
list
from [[Yoga MOC]]
```
Or going _out of_ a note:
```dataview
list
from outgoing([[yoga MOC]])
```
- This syntax may change in an upcoming release.
#### Combining Sources
You can use the 3 basic logical operators to create more complex `from` queries:
- `list from #A and #B`
- `list from "University" or "Work"`
- `list from -#Personal`
- `list from [[CSS]] and -#HTML`
#### String Concatenation
In the results of a `list`, you can include metadata fields joined with strings
```dataview
list "File Path: " + file.path + " :)"
from #SN
```
#### Lists of lists
A `list` can also display indented sublists of metadata:
```dataview
list authors
from #SN/Blog
```
### `Task`
`Task` searches for all checkboxes `- [ ] ` in your vault.
It returns a list of all tasks, grouped by their parent note
```dataview
task from #MOC
```
### `Where`
After choosing _which_ notes to use, you can narrow down the list further using a `where` block.
This lets you use the various _comparison operators_ on the metadata fields in your notes.
`>`, `>=`, `<`, `<=`, `=`, `!=`
`where {condition}`
#### Examples
- `where file.size > 1000`
- `where file.name != "2021-04-09 Daily Note"`
- `where file.mtime >= date(today) - dur(1 day)`
- `where !complete`
### `Table`
`Table` can show you a _table_ of various metadata fields linked to each note.
`Table {field 1}, {field 2}, ...`
#### Examples
```dataview
table intensity
from #Uni/2021/Asg
```
```dataview
table title, type
from #SN
```
```dataview
table file.tags
from Kw/Yoga
```
### `Sort`
You can use `sort` to define which order to list the results in, and which `field` to sort by:
`sort field asc/desc`
Give multiple fields to decide ties
`sort field1 asc/desc, field2 asc/desc, ...`
### `Flatten`
Use `flatten` to "unroll" lists into their own rows.
```dataview
table authors from #SN
```
<center>versus</center>
```dataview
table authors from #SN
flatten authors
```
### `Group by`
`Group by` lets do gather together results based on the value of a field.
You may group:
- tasks by `completed`
- games by `rating`
- assignments by `intensity`
First, gather all the assignments:
`from #Uni/2021/Asg`
Then, group by `intensity`:
`group by intensity`
#### `rows` Object
By grouping the notes, we've created a **new object**.
This is a **nested list** of all the assignments grouped by intensity.
Something like:
```js
[
[A1, A2, A6], // Green
[A3, A4], // Yellow
[A5, A7], // Red
];
```
To access this new list, we use the `rows` object.
- Get the file name of every note in the array: `rows.file.name`
- Get the due date of every note: `rows.dueDate`
```dataview
table intensity, rows.title
from #Uni/2021/Asg
group by intensity
```
#### Group by tags
```dataview
table rows.file.tags, rows.file.link
from #Fi/Yoga
group by file.tags
```
##### Limitations
It will only consider two notes to be in the same group if they have **exactly the same tags**.
- So even if two notes have `#Note/Author`, if the one has a tag that the other doesn't, they won't be grouped together.
## Functions
### `Contains()`
Used to see if:
- a `string` _contains_ a substring
- a `list` _contains_ a value
`where contains(file.name, "Daily Note")`
`where contains(authors, "Robert Lamb")`
### `Length()`
Returns the _length_ of a `string` or `list`
`where length(file.name) > 10`
### `Sum()`
Returns the _sum_ of the numbers in a `list`
`where sum(minutesStudied) < 60`
### Many other Functions
For further info on implemented functions, head over to [the official documentation](https://blacksmithgu.github.io/obsidian-dataview/#/functions).
## Neat Examples
People have come up with a lot of interesting ways of leveraging Dataview. Many have been shared in the central [Dataview Snippet Showcase](https://forum.obsidian.md/t/dataview-plugin-snippet-showcase/13673) on the Obsidian Forum.
### Untagged Notes
For example, finding all untagged notes in your vault is as simple as:
`list where length(file.tags) = 0`
### Birthdays
If you track \#People in separate notes and add their Birthday as a dataview property, you could compile a list of everyone whose birthday is today like this:
```dataview
list from #People
where Dates.Birthday = "<% tp.date.now(format = "YYYY-MM-DD") %>"
```
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