Grouping Data in Supabase: A Beginner's Guide with Examples

Supabase's JavaScript SDK library doesn't support complex queries like grouping data. Luckily, the platform's SQL Editor lets you perform advanced queries on your Postgres database. You can create a SQL view that performs the query and treat it like a table that can be queried using the Supabase JavaScript SDK library.

To create a SQL view, we can navigate to the SQL Editor in the Supabase dashboard and write our SQL query. Here's an example of a SQL view that groups data by a particular column:

CREATE VIEW my_view AS
SELECT grouped_column, COUNT(*)
FROM my_table
GROUP BY grouped_column;

This SQL query creates a view named my_view that groups data from a table named my_table by a column named grouped_column. It then counts the number of rows in each group and returns the result.

Once we've created the SQL view, we can query it from the Supabase JS library like any other table:

import { createClient } from '@supabase/supabase-js'

const supabaseUrl = 'https://your-project-url.supabase.co'
const supabaseKey = 'your-anon-key'
const supabase = createClient(supabaseUrl, supabaseKey)

supabase
  .from('my_view')
  .select('*')
  .then((data, error) => {
    if (error) {
      console.error(error)
      return
    }
    console.log(data)
  })

In this example, we're querying the my_view view that we created earlier. We're using the select method to select all columns from the view. We can now perform any other operations on the data that we need to.

Example of grouping by month and year

Sure, here's an example query that groups data by both month and year:

CREATE VIEW my_view AS
SELECT
  DATE_TRUNC('month', created_at) AS month,
  DATE_TRUNC('year', created_at) AS year,
  COUNT(*) AS count
FROM
  my_table
GROUP BY
  month,
  year;

This query creates a view named my_view that groups data from a table named my_table by both month and year of the created_at column. The DATE_TRUNC function is used to extract the month and year from the created_at column. The COUNT function is used to count the number of rows in each month and year group. The result is a table with three columns: month, year, and count.

You can then query this view from the Supabase JavaScript SDK library like this:

import { createClient } from '@supabase/supabase-js'

const supabaseUrl = 'https://your-project-url.supabase.co'
const supabaseKey = 'your-anon-key'
const supabase = createClient(supabaseUrl, supabaseKey)

supabase
  .from('my_view')
  .select('*')
  .then((data, error) => {
    if (error) {
      console.error(error)
      return
    }
    console.log(data)
  })

This will return the result of the view, which will include the month, year, and count columns for each group. You can modify the view's query to group by other date/time periods as well, depending on your needs.

I hope this clears things up!