Basics

Indentation

We use 2-space tab indentation

SELECT
  partners.id             AS partner_id,
  partners.image_url      AS image,
  partners.partner_email  AS email,
  partners.active         AS is_active
FROM prod_db.partners

Use of spaces

For clarity and readability, use spaces in after commas, between numbers and mathematical signs

SUM(100 / 2) instead of SUM(100/2)

IF(status = 'Active') instead of IF(status='Active')

COALESCE(created_at, started_at) instead of COALESCE(created_at,started_at)

Styling

WITH data AS (
  SELECT DISTINCT
    * EXCEPT(field_1, field_2),
    created_at,
    ended_ad,
    modified_by,
    IF(field IS NULL, 0, 500) AS field,
    CASE
      WHEN created_at IS NOT NULL THEN TRUE
      WHEN created_at > '2022-02-01' THEN FALSE
      ELSE NULL
    END AS another_field,
    (amount / 100) * 2 AS number_field,
    status = active AS boolean_field
  FROM database.schema.table short
    LEFT JOIN database.schema.other_table os ON os.date = short.created_at
    LEFT JOIN cte_join USING(modified_by)
    PIVOT(
      SUM(amount) FOR month IN('January', 'February', 'March')
    ) AS p (colum_name, jan, feb, mar)
    LATERAL(TABLE(FIBONACCI_SEQUENCE_UDF(6.0::FLOAT))) 
  WHERE
    created_at > '2022-01-01'
    AND modified_by IS NOT NULL
  GROUP BY
    1, 2
  HAVING
    COUNT(DISTINCT status) > 0
  QUALIFY
    ROW_NUMBER() OVER(PARITION BY modified_by) = 1
  ORDER BY 
    1 DESC,
    2 ASC
  LIMIT 100
)

SELECT
  created_at,
  ended_at,
  modified_by,
  field,
  another_field,
  number_field,
  boolean_field
FROM data

Syntax option availability may differ from dialect to dialect, and their versions.

Main keywords after which the references go to new line with indentation

SELECT
  <fields>
CASE
  <when|else>
FROM <table>
  <join>
PIVOT
  <statement>
WHERE
  <condition>
GROUP BY
  <field>
HAVING
  <condition>
ORDER BY
  <field>

Those are keywords that usually follow by a list of references to fields.

Keywords that require "completion"

FROM <table>
LEFT JOIN <table> <alias> ON <field> = <field>
INNER JOIN <table> USING(<field>)
PIVOT(AGG(<field>) FOR <field> IN (<value>, <value>)) <alias>
LATERAL(TABLE())

Exceptions

If it's a simple SELECT * query that is used for multiple UNIONs, you can write it in one line, if it doesn't require you to list all the columns

SELECT * FROM table_a UNION ALL
SELECT * FROM table_b

Keywords that are only followed by one number reference.

GROUP BY 1
ORDER BY 2
LIMIT 100

JOIN has many conditions and they can't be replaced with USING

FROM table
  LEFT JOIN other_table t ON t.user_id = table.user_id
                             AND t.date = table.date
                             AND t.country = table.country
                             AND t.currency = table.other_currency