MYSQL 行转列 Pivot 动态 思路

SQL Server行转列、不确定列的行转列 - 农村的码农 - 博客园
https://www.cnblogs.com/kylan/p/10844414.html

mysql 行转列 列转行 - 平凡希 - 博客园
https://www.cnblogs.com/xiaoxi/p/7151433.html

Pivot Tables in MySQL
https://codingsight.com/pivot-tables-in-mysql/

Pivoting in MySQL
http://mysql.rjweb.org/doc.php/pivot

MySQL - Creating a pivot query | mysql Tutorial
https://riptutorial.com/mysql/example/10441/creating-a-pivot-query

Mysql - MySQL Pivot Handling Values
https://www.howtobuildsoftware.com/index.php/how-do/cnlj/mysql-pivot-mysql-pivot-handling-values

How can I return pivot table output in MySQL? - Stack Overflow
https://stackoverflow.com/questions/7674786/how-can-i-return-pivot-table-output-in-mysql

Artful Common Queries
http://www.artfulsoftware.com/infotree/qrytip.php?id=78