get_indexes_sql() fails on MySQL < 8.0.13 and MariaDB (missing EXPRESSION column) #1436

get_indexes_sql() in src/datajoint/adapters/mysql.py queries COALESCE(COLUMN_NAME, CONCAT('(', EXPRESSION, ')')) from information_schema.STATISTICS, but the EXPRESSION column only exists in MySQL 8.0.13+. On MySQL 5.7 or MariaDB, this fails with Unknown column 'EXPRESSION' in 'field list' the first time any table class is decorated with @schema.

Introduced in commit bd35a7e (PR #1338). Prior to that, the query just selected COLUMN_NAME directly.

A fallback for when EXPRESSION isn't available would fix this for both MySQL < 8.0.13 and MariaDB.