cockroachdb-sql

name	cockroachdb-sql
description	Use when writing, generating, or optimizing SQL for CockroachDB, designing CockroachDB schemas, or when the user asks about CockroachDB-specific SQL patterns, type mappings, and distributed database best practices. Also use when encountering CockroachDB anti-patterns like missing primary keys, sequential ID hotspots, or incorrect type usage.
compatibility	Can work with or without connection to a database. Without connection it generates the SQL and gives instruction for connection.With connection it requires appropriate privilege on target database and tables (SELECT, INSERT, UPDATE, DELETE, or admin).
metadata	{"author":"cockroachdb","version":"1.0"}

CockroachDB SQL Skill

Converts natural language questions into CockroachDB-compliant SQL queries, following CockroachDB best practices. Use it for schema design, writing queries and optimizing query.

How to Apply this Skill

1. Connection Detection — already performed on skill invocation; reuse active connection.

2. Parse Natural Language Intent

   • Identify the operation type (SELECT, INSERT, UPDATE, DELETE, CREATE, ALTER, etc.)

3. Context Gathering

   • Check for existing schema context in conversation
   • If connected to DB, query existing schema:
     • SHOW TABLES; to see existing tables
     • SHOW CREATE TABLE table_name; for existing structure
   • Ask clarifying questions if needed:
     • Table structure if not provided
     • Data types for columns
     • Index requirements
     • Multi-region needs
     • Performance characteristics

4. Apply CockroachDB Rules

   • Reference rules in references/cockroachdb-rules/
   • Ensure compliance with CockroachDB best practices
   • Determine rule category based on operation and apply the relavant rules:
     • 00-fundamental-principles.md - Always apply these first
     • 01-schema-design.md - Table creation and structure
     • 02-dml-operations.md - Data modification
     • 03-query-patterns.md - Query construction
     • 04-optimization.md - Performance, Optimization and anti-patterns
     • 05-operational.md - Admin and maintenance
   • Validate against anti-patterns in 04-optimization.md

5. Validate against DB(MANDATORY)

   • ALWAYS run EXPLAIN on every generated SQL query when connected to DB.
   • If EXPLAIN returns a parsing/syntax error, fix the query and re-run EXPLAIN until it passes.
   • Include the EXPLAIN output in the response.

Response Behavior

Initial Response

When skill is invoked, ALWAYS:

1. Immediately detect connection before any other action or response:

   • Check if connection string is provided in the prompt (postgresql://...).
     • If provided, use cockroach sql --url "<provided-url>" -e "SQL" to run queries. Do not use psql.
   • Else check COCKROACH_URL environment variable (echo $COCKROACH_URL).
     • If set, use cockroach sql --url $COCKROACH_URL -e "SQL" to run queries. Do not use psql.
   • Else check for cockroach-cloud MCP server availability

2. Focus exclusively on CockroachDB

3. Emphasize "natural language to CockroachDB SQL" not "database conversion"

4. Keep user-facing content CockroachDB-specific regardless of internal PostgreSQL rules.

Output Format

• Show generated SQL with explanatory comments
• List CockroachDB-specific features used
• Include performance considerations
• When optimizing, at each step 1- Explain the step's purpose. 2- Execute the step and report the outcome. 3- Summarize all findings and actions taken.
• Provide references used including the rules

Examples

Schema Design — UUID Primary Key (Avoid Hotspots)

CREATE TABLE orders (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  customer_id UUID NOT NULL,
  status STRING NOT NULL DEFAULT 'pending',
  total DECIMAL(10,2) NOT NULL,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
  INDEX idx_orders_customer (customer_id),
  INDEX idx_orders_status_created (status, created_at DESC)
);

Batch Upsert with UNNEST

UPSERT INTO inventory (sku, warehouse, quantity, updated_at)
SELECT * FROM UNNEST(
  ARRAY['SKU-001', 'SKU-002', 'SKU-003']::STRING[],
  ARRAY['us-east', 'us-east', 'us-west']::STRING[],
  ARRAY[100, 250, 75]::INT[],
  ARRAY[now(), now(), now()]::TIMESTAMPTZ[]
);

Keyset Pagination (Avoid OFFSET)

Use the previous page's last (created_at, id) as the cursor. In application code these are bound parameters; the literals here are placeholders.

SELECT id, customer_id, created_at
FROM orders
WHERE (created_at, id) > ('2025-01-01'::TIMESTAMPTZ, '00000000-0000-0000-0000-000000000000'::UUID)
ORDER BY created_at, id
LIMIT 50;

Supporting Documentation

• references/cockroachdb-rules/ - CockroachDB SQL rules
• references/EXAMPLES.md - SQL examples and patterns