modern-sql-style

An agent skill that teaches AI coding assistants your SQL style guide.

When installed, your AI agent will automatically apply these conventions whenever writing or reviewing SQL — both DML (queries) and DDL (schema definitions). Covers lowercase keywords, river formatting, leading commas, explicit as aliases, column-aligned DDL, and more.

Based on mattmc3's Modern SQL Style Guide for DML, with DDL conventions derived from real-world data engineering practice.

Install

npx skills add modern-sql-style

Or, to install directly from this repo:

npx skills add meteoFurletov/modern-sql-style

What It Enforces

DML

Rule	Convention
Keywords	lowercase (select, from, where, …)
Formatting	river alignment (right-aligned keywords)
Commas	leading (prefix) commas
Aliases	always use as keyword
Joins	join / left join only; no right join
Subqueries	prefix alias with _
Semicolons	on their own line
Dates	ISO-8601, UTC storage

DDL

Rule	Convention
Keywords	lowercase (create table, engine, …)
Naming	PascalCase for databases/tables
Columns	double-quoted, ( / , aligned, column-aligned types & comments
Commas	leading commas, , aligned with (
Comments	comment '…' after every type and table
Clauses	engine → order by → comment, no blank lines

Note: The DDL conventions are written with ClickHouse in mind. The formatting principles apply to any SQL database, but engine-specific syntax (MergeTree, order by as a primary key, etc.) will need to be adapted for PostgreSQL, MySQL, or other dialects.

Quick Examples

DML (Queries)

select p.name as product_name
     , p.color
     , p.list_price
  from production.product as p
 where p.color in ('Blue', 'Red')
   and p.list_price < 800.00
 order by p.name

DDL (Schema)

create table Inventory.Product
( "ProductId"    Int64       comment 'Unique product identifier'
, "ProductName"  String      comment 'Display name'
, "CategoryCode" String      comment 'Category reference code'
, "Price"        Float64     comment 'Unit price'
, "IsActive"     Bool        comment 'Whether the product is active'
, "Tags"         Array(JSON) comment 'Arbitrary metadata tags'
)
engine = MergeTree()
order by ("CategoryCode", "ProductId")
comment 'Product catalogue'

Supported Agents

Works with any agent that supports the agent skills spec:

• GitHub Copilot
• Claude Code
• Cursor
• Windsurf
• and more

License

CC BY-SA 4.0 — same as the upstream style guide.