Oracle one-to-many organize multiple rows of data into one row

A one-to-many relationship in development is often used, and yesterday a customer problem was asked to organize the information for all feedback tasks into a single line to show and export Excel.

My database correspondence: The feedback task task corresponds to multiple feedback, which means that each task has a lot of feedback cycles. Requires crawling of all feedback information for each task.

Task table:

Feedback table:

Use the Wmsys.wm_concat function for processing:

Select Task_id,wmsys.wm_concat (T.CONTENTSS) as contentsum from Zx_gzdb_feedback t where task_id = ' 201706261036120392116914415206 ' GROUP by task_id;

Output Result:

Oracle one-to-many organize multiple rows of data into one row