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CSA Loom — the Microsoft Fabric experience for Azure tenants where Fabric isn't yet available: lakehouses, warehouses, notebooks, semantic models, Activator rules, Data Agents, across Commercial, GCC, GCC-High, and DoD IL5

Warehouse SQL

The Loom warehouse surface is a fully-managed T-SQL data warehouse: storage on OneLake (Parquet/Delta), auto-scaling compute, no infrastructure to manage. The SQL query editor builds the Fabric Warehouse / Synapse SQL experience one-for-one — write T-SQL, run it against the real endpoint, and see results, cost, and bytes processed.

When to use it

  • Serve curated Gold-layer tables to BI in T-SQL, with cross-database joins across any lakehouse SQL endpoint or mirrored database in the workspace.
  • DirectLake semantic models for sub-second Power BI refresh over the warehouse.
  • Ad-hoc SQL analytics over Delta tables produced by notebooks or pipelines.

For pay-per-query exploration over files in storage (no provisioned warehouse), use the Synapse serverless SQL pool surface and OPENROWSET instead.

The SQL query editor

Open the warehouse at /items/warehouse/<id>. The ribbon mirrors Fabric/Synapse:

  • Home — connection + run controls.
  • Query — New SQL query, Run.
  • The schema explorer lists databases, schemas, tables, and External tables.
  • For serverless, the editor also surfaces Cost, Bytes processed, and a Cost cap — so you see the price of a scan before and after running.

Step-by-step: create, load, query

  1. New SQL query from the ribbon. A blank T-SQL editor opens with the schema tree alongside.
  2. Run standard DDL/DML — Loom executes it over the real TDS/SQL endpoint:
CREATE TABLE dbo.sales_gold (
    sale_date date, region varchar(50), revenue decimal(18,2));

INSERT INTO dbo.sales_gold
SELECT CAST(date AS date), region, SUM(amount)
FROM   silver_sales
GROUP BY CAST(date AS date), region;
  1. Cross-database query any lakehouse SQL endpoint or mirrored database in the same workspace with three-part names:
SELECT g.region, g.revenue, c.tier
FROM   dbo.sales_gold g
JOIN   [mirror_crm].dbo.customers c ON c.region = g.region;
  1. Run (toolbar or Ctrl+Enter). Results appear in the bottom grid; on serverless the Bytes processed / Cost read-outs update so you can tune scans.
  2. Connect Power BI in DirectLake mode against the warehouse for sub-second semantic-model reads — no import refresh.

Serverless cost discipline

When the endpoint is Synapse serverless, billing is metered by bytes scanned. Filter on partitioned columns (year/month/day), select only the columns you need, and read Parquet/Delta directly with OPENROWSET(BULK ..., FORMAT='PARQUET') / FORMAT='DELTA'.

Honest infra gate

If no SQL endpoint is wired, the editor shows a MessageBar naming the server binding / Entra admin required — the query editor and schema tree still render.

Learn more