Understanding and Exploring SQ4CDS: A Query Language for Common Data Service

Structured Query Language (SQL) is a fundamental tool for managing and extracting data efficiently in relational databases. For users of the Microsoft Power Platform and Common Data Service (CDS), SQL for CDS (Structured Query Language for Common Data Service), often abbreviated as SQ4CDS, is a powerful query language designed specifically for working with CDS entities. In this blog post, we will explore SQ4CDS, its syntax, and provide practical examples of how to select, update, and delete records using this versatile query language.

What is SQ4CDS?

SQ4CDS is an SQL variant customized for the Common Data Service, a secure and scalable data platform within the Microsoft Power Platform. It enables you to efficiently manage and access data stored in CDS entities, apply filtering conditions, and execute complex queries similar to SQL in relational databases.

Key Features of SQ4CDS:

1. Data Querying: Retrieve data from CDS entities using SQL-like queries.
2. Filter Expressions: Apply conditions to filter data with WHERE clauses.
3. Sorting: Sort results using ORDER BY clauses.
4. Joining Entities: Access related data from multiple entities with JOIN clauses.
5. Grouping and Aggregation: Use GROUP BY and aggregate functions like SUM, AVG, MIN, and MAX.

Using SQ4CDS: Basic Query Example

To effectively utilize SQ4CDS, familiarize yourself with the syntax and available entities in your CDS environment. Here's a simple example of a query that selects records:

sql
SELECT fullname, birthdate
FROM contact
WHERE statecode = 0
ORDER BY birthdate

In this example:

• We select the "fullname" and "birthdate" columns from the "contact" entity.
• We filter records where the "statecode" is equal to 0 (active contacts).
• We order the results by the "birthdate" column.

Now, let's explore more advanced queries and operations:

1. Updating Records

Updating records in SQ4CDS is straightforward. Use the UPDATE statement to modify data in your CDS entities. Here's an example that sets the "emailaddress1" field to a new email for active contacts:

sql
UPDATE contact
SET emailaddress1 = 'newemail@example.com'
WHERE statecode = 0

In this query:

• We update the "emailaddress1" field to the new email value.
• We apply the change to records with a "statecode" of 0 (active contacts).

2. Deleting Records

Deleting records in CDS entities can be done with the DELETE statement. In this example, we delete all inactive contacts:

sql
DELETE FROM contact
WHERE statecode = 1

Here's what the query does:

• It removes all records with a "statecode" of 1 (inactive contacts).

Advanced Examples:

Let's explore more advanced scenarios with SQ4CDS:

3. Joining Entities

SQ4CDS allows you to join entities, enabling you to work with related data effectively. Here's a query that retrieves contact information along with associated opportunity data:

sql
SELECT c.fullname, o.name
FROM contact AS c
INNER JOIN opportunity AS o ON c.contactid = o.customerid
WHERE o.actualclosedate IS NOT NULL

In this example:

• We select "fullname" from contacts and "name" from opportunities.
• We create aliases (c and o) for the contact and opportunity entities.
• We join contact and opportunity records based on the "contactid" and "customerid" fields.
• We filter records with a non-null "actualclosedate" from opportunities.

4. Aggregating Data

Aggregation functions help summarize data. Here's an example that calculates the average revenue of won opportunities for each customer:

sql
SELECT o.customerid, AVG(o.estimatedvalue) AS avg_revenue
FROM opportunity AS o
WHERE o.statecode = 1
GROUP BY o.customerid

In this query:

• We select the "customerid" and calculate the average estimated value ("estimatedvalue") for each customer.
• We filter for opportunities with a "statecode" of 1 (won opportunities).
• We group results by "customerid."

Conclusion

SQL for CDS (SQ4CDS) is a potent tool for efficiently managing and extracting data within the Common Data Service environment. With the ability to select, update, and delete records, as well as advanced operations like joining entities and aggregating data, SQ4CDS empowers users to work with CDS entities effectively. By mastering this query language, you can maximize the capabilities offered by the Microsoft Power Platform and the Common Data Service.