improve SQL

docs/engineering-guide/sysdb_environments.md

@@ -155,5 +155,5 @@ To remove a Sysdb environment follwoing steps are required:
     ```bash
     cd /var/www/sysdb
     sqlite3 inv.db
-    DELETE from environments WHERE name = "<environment_name>";
+    DELETE FROM environments WHERE name = '<environment_name>';
     ```