CTE not found

Hi,

When trying to find a workaround for jira MDEV-13730, I generated a new code which does not use too many CTEs in the same scope.

This is a sample new SQL code :

https://raw.githubusercontent.com/antoinecarme/sklearn2sql-demo/master/tests/mariadb/MDEV-13730/new/GradientBoostingClassifier/iris/mysql/demo2_GradientBoostingClassifier_mysql.sql

and when executed, it outputs the error :

1146, "Table 'db.DT_node_lookup' doesn't exist"

There is no such table, but a CTE is defined in the SQL code with the same name.

At first, the last error seems to be a CTE resolution issue when CTEs are defined inside CTEs.

I am working on debian, with a mariadb version 10.2.8.

Thanks in advance

Antoine