Скачать или смотреть How to Fetch Records with 100% row_status = 0 Across Multiple Business Units in SQL

Learn how to write an efficient SQL query to identify service codes with 100% `row_status = 0` across all business units in your data tables.
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This video is based on the question https://stackoverflow.com/q/77745010/ asked by the user 'Ankita Biswas' ( https://stackoverflow.com/u/1730657/ ) and on the answer https://stackoverflow.com/a/77745051/ provided by the user 'Sergey' ( https://stackoverflow.com/u/14535517/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem: Fetching Service Codes with Specific Row Status

In the realm of data management, particularly when working with SQL, users often need to sift through vast amounts of records to extract useful information. One common task is determining which service codes have a specific status across multiple categories—in this case, identifying service codes that have a row_status = 0 across all business_unit_ids.

Let’s walk through a real-life scenario on how to achieve this by using a structured SQL query.

The Scenario

Consider you have a table named disp, containing three columns:

service_code: Represents the type of service.

row_status: Indicates the status of the service (0 or 1).

business_unit_id: Identifiers for various business units.

Here’s how a simplified version of the table looks:

service_code
row_status
business_unit_id
A
1
BU1
A
0
BU2
A
0
BU3
B
1
BU1
B
0
BU2
C
0
BU2
C
0
BU3

Your goal is to find the service codes that have all their row_status values as 0 across every business unit listed. According to the sample data above, the only service code that fulfills this requirement is C.

The Solution

To find the service codes that meet the criteria stated above, we can use a SQL query that utilizes a Common Table Expression (CTE). Below is the method to accomplish this:

Step 1: Create a Common Table Expression (CTE)

Start by defining your data source. In this case, we emulate the data within the CTE. This step is essentially creating a temporary view with your table's data:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Querying the Data

Next, we perform a query to identify the service codes. To ensure we only get the service codes with a row_status of 0 across all instances, we use the GROUP BY and HAVING clauses as shown below:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Explanation of the Query

GROUP BY: This groups the results by service_code, allowing us to perform aggregate functions on each group.

HAVING: This clause filters the grouped results based on specified conditions:

MIN(C.row_status) = MAX(C.row_status): This ensures all statuses for a given service code are the same.

MIN(C.row_status) = 0: This confirms that the only status present is 0.

Conclusion

Using the provided SQL query, you can successfully identify service codes with a row_status = 0 across all business units, efficiently querying even large datasets. By understanding how to structure your queries with CTEs and aggregate functions, you'll be better equipped to handle similar data challenges in the future.

Remember, the key takeaway is the clarity of the conditions you're placing in your SQL HAVING clause to ensure accurate retrieval of records.

If you have any questions or need further clarification, feel free to reach out in the comments!