Getting Started with Computed Tables

Use Computed Tables when you want to perform the following operations on your selected source datastores:

• Data Preparation and Transformation: Clean, shape, and restructure raw data from JDBC source datastores.
• Complex Calculations and Aggregations: Perform calculations not easily supported by standard containers.
• Data Subsetting: Extract specific data subsets based on filters using SQL's WHERE clause.
• Joining Data Across Source Datastores: Combine data from multiple JDBC source datastores using SQL joins.

Add Computed Tables

Step 1: Log in to your Qualytics account and select a JDBC-type source datastore from the side menu on which you would like to add a computed table.

Step 2: After selecting your preferred source datastore, you will be redirected to the source datastore operations page. From this page, click on the Add button and select the Computed Table option from the dropdown menu.

Step 3: A modal window will appear prompting you to enter a name for your computed table, a valid SQL query that supports your selected source datastore, and optionally, additional metadata.

Step 4: Click on the Validate button to instantly check the syntax and semantics of your SQL query. This ensures your query runs successfully and prevents errors before saving.

Step 5: Once validation is successful, click on the Save button to add the computed table to your selected source datastore.

Query Diff for Computed Tables

Computed Tables now include a side-by-side query diff view in the History panel, allowing you to compare previous and updated SQL versions. This makes it easy to identify changes, troubleshoot issues, and maintain better audit visibility of query modifications.

Limitations

Referencing Other Computed Tables

A computed table cannot directly reference another computed table in its SQL query. For example, attempting to write a query like this will fail:

SELECT * FROM my_computed_table JOIN another_computed_table ON ...

Why this happens: Computed tables are defined and stored within Qualytics, but they are not created as actual database objects (like views or tables) in your data warehouse. When your SQL query runs, the database engine cannot find my_computed_table because it doesn't exist as a named object in the warehouse catalog.

Workarounds

If you need to combine logic from multiple computed tables, you have several options:

Option 1: Combine Logic Using CTEs

Merge the SQL logic into a single computed table using Common Table Expressions (CTEs):

WITH dataset_a AS (
    SELECT id, name, amount
    FROM source_table_1
    WHERE status = 'active'
),
dataset_b AS (
    SELECT id, category, region
    FROM source_table_2
    WHERE year = 2024
)
SELECT
    a.id,
    a.name,
    a.amount,
    b.category,
    b.region
FROM dataset_a a
JOIN dataset_b b ON a.id = b.id

This approach works because the entire query is executed as a single unit by the database engine.

Option 2: Create a View in Your Data Warehouse

If you need to reuse intermediate results across multiple computed tables:

1. Create a view or table directly in your data warehouse (e.g., using your warehouse's SQL interface or a tool like dbt).
2. Catalog that view or table in Qualytics.
3. Reference the cataloged object in your computed table queries.

This works because the intermediate result becomes a real, queryable object in your warehouse.

Using Computed Tables in Computed Joins

Computed Tables can be used as the left side, the right side, or both sides of a Computed Join, alongside base tables, views, DFS files, and Computed Files. This lets you reuse SQL-defined logic (filters, aggregations, transformations) across multiple joins without re-expressing it in each Select Expression. The only restriction is that another Computed Join cannot be used as a join input. For the full list of supported inputs, see Computed Join Supported Inputs.

Computed Tables vs Computed Files

Computed Tables and Computed Files both let you generate transformed datasets, but they differ in how the output is stored, processed, and consumed:

For Computed Files, see Getting Started with Computed Files.

Editing from Checks

Computed tables and files can also be edited directly from check interfaces. This lets you quickly update computed logic when resolving check failures.

View Assigned Teams

Hover over the information icon to view the teams assigned to this computed asset.