How can I write flexible and reusable SQL queries using Galaxy SQL conventions?

Use Galaxy’s parameterization syntax, modular CTE structure, and Collections to turn any query into a reusable building block that adapts to new filters, tables, or teams in seconds.

Why does flexible, reusable SQL matter?

Hard-coded filters and copy-pasted snippets slow teams down and hide logic. Reusable SQL cuts maintenance time, improves trust, and lets Galaxy’s AI Copilot optimize once for every future use.

What Galaxy conventions make queries reusable?

1. Parameter placeholders

Wrap filter values in {{ param_name }}. Galaxy validates types, prompts users at run-time, and stores default values so the same query works in dev, staging, and prod.

2. CTE-first design

Move every logical step into a named CTE. Galaxy’s editor shows lineage between CTEs, making it easy to swap inputs or reuse just the final CTE in another report.

3. Consistent aliasing

Always alias tables with the singular noun (e.g., FROM orders o). The Copilot recognizes this convention and autocompletes joins correctly.

How do I parameterize queries in Galaxy?

Declare parameters at the top with an inline comment:

-- @param start_date::date = CURRENT_DATE - 30
-- @param end_date::date = CURRENT_DATE
SELECT ... WHERE created_at BETWEEN {{start_date}} AND {{end_date}};

Galaxy renders a date-picker UI, so non-SQL users can run the same query without editing code.

Can I store and version reusable queries?

Save the query inside a Collection and click Endorse. Galaxy adds it to workspace search, tracks every edit, and blocks unapproved changes to protect downstream dashboards.

How does the AI Copilot help?

The Galaxy AI Copilot rewrites legacy SQL into the parameterized, CTE-first style. It also explains each CTE in plain English so future contributors know exactly what to reuse.

Practical tips for modular Galaxy SQL

• Reference common dimension tables (e.g., dim_users) instead of re-writing CASE logic.
• Use WITH base AS (...) plus , filtered AS (...) pattern to expose hook points for new filters.
• Add a final SELECT that only exposes clean, business-friendly column names.

Reusable query template

-- @param customer_id::int
-- @param as_of::date = CURRENT_DATE
WITH
base AS (
SELECT *
FROM fact_events fe
WHERE fe.customer_id = {{customer_id}}
),
daily AS (
SELECT DATE_TRUNC('day', occurred_at) AS day, COUNT(*) AS events
FROM base
WHERE occurred_at <= {{as_of}}
GROUP BY 1
)
SELECT day, events FROM daily ORDER BY day;

Save and endorse this template in a Galaxy Collection; teammates can now run it by supplying only customer_id.

Next steps

Start refactoring your highest-traffic queries with these conventions. Then let Galaxy’s versioning, permissions, and AI complete the loop-so your SQL stays flexible well into 2025 and beyond.