How to Connect SQL Server to Looker

Galaxy Glossary

How do I connect Microsoft SQL Server to Looker?

Securely configure Looker to query data stored in Microsoft SQL Server.

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Description

Example H2

Example H3

Why connect SQL Server to Looker?

Looker can only visualize data held in a database it can reach. Adding SQL Server lets analysts create dashboards without copying data.

What prerequisites must be met?

Confirm you have (a) a SQL Server hostname or IP, (b) a SQL login with read rights, (c) the port open (default 1433) to the Looker IP(s), and (d) SSL certificates if required.

How do I add the connection in Looker?

Navigate to Admin → Connections → New Connection. Choose “Microsoft SQL Server.” Supply the values below, save, and test.

Required parameters

Name: lowercase, no spaces (ex: sqlserver_ecommerce)
Host: db.company.com
Port: 1433
Database: ecommerce
Username/Password: service account

Optional parameters

SSL: enable to encrypt traffic.
PDT Support: allow Looker to create Persistent Derived Tables.

How do I verify the connection?

Open SQL Runner, pick the new connection, and run a simple query such as:

SELECT TOP 5 id, name, email FROM Customers ORDER BY created_at DESC;

Best practices for production

Grant the Looker user read-only access to base schemas and db_ddladmin or a dedicated schema for PDTs only when needed. Monitor query cost with SQL Server DMVs.

How to troubleshoot failed tests?

“Could not connect” → verify firewall and SSL settings.
“Login failed” → confirm SQL authentication (not Windows) and password.
“Database unavailable” → check the chosen default database exists.

Can I limit Looker to specific tables?

Create a user-mapped role and grant SELECT only on needed tables, e.g. GRANT SELECT ON dbo.Orders TO looker_ro;

Why How to Connect SQL Server to Looker is important

How to Connect SQL Server to Looker Example Usage


-- Check last 10 high-value orders in Looker SQL Runner
SELECT TOP 10 o.id,
       c.name AS customer_name,
       o.order_date,
       o.total_amount
FROM   Orders      o
JOIN   Customers   c ON c.id = o.customer_id
WHERE  o.total_amount > 500
ORDER BY o.order_date DESC;

How to Connect SQL Server to Looker Syntax


-- Looker connection settings (YAML-like for clarity)
connection_name: sqlserver_ecommerce
host: db.company.com
port: 1433
database: ecommerce
username: looker_ro
password: ********
ssl: required|optional
pdt_storage_database: looker_temp

-- Permission script run in SQL Server
CREATE LOGIN looker_ro WITH PASSWORD = 'StrongPass!2024';
CREATE USER looker_ro FOR LOGIN looker_ro;
EXEC sp_addrolemember 'db_datareader', 'looker_ro';  -- read all tables
GRANT SELECT ON dbo.Customers  TO looker_ro;          -- fine-grained example
GRANT SELECT ON dbo.Orders     TO looker_ro;

Common Mistakes

Using Windows Authentication. Looker requires SQL authentication; create a SQL login with a strong password to avoid connection failures.
Granting dbo rights. Over-permissive roles risk accidental data changes; instead assign read-only plus a separate schema for PDT writes.

Frequently Asked Questions (FAQs)

Do I need to install a driver?

No. Looker’s hosted platform already bundles the Microsoft JDBC driver. For customer-hosted Looker (Looker on prem), install mssql-jdbc-<ver>.jar in the drivers folder.