How Can I Retrieve All Employee Records for a Specific Organization in a Single SQL Query?

Retrieving Multiple Employee Records Associated with an Organization in a Single Result Set

The task at hand involves fetching all the details of a specified organization along with the first names of its employees. To tackle this challenge, one must consider a database-vendor-specific approach, as no universal solution exists in SQL-92 or SQL-99.

In the case of MySQL, the GROUP_CONCAT function allows for efficient retrieval of concatenated values. A query utilizing this function could resemble the following:

PostgreSQL 9.0 provides an equally straightforward solution with the STRING_AGG function:

For versions of PostgreSQL prior to 9.0, the CREATE AGGREGATE command allows for custom aggregate function definitions.

Oracle employs LISTAGG for similar functionality, while MS SQL Server uses STRING_AGG.

In the absence of built-in group concatenation functions, a fallback option involves creating a stored procedure that accepts the organization ID as its input and returns the concatenated employee names. This stored procedure can then be utilized within a query:

By employing these vendor-specific approaches, it is feasible to retrieve multiple employee records pertaining to a single organization in a single result set.

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