Fixed duplicate plan_user_info removal on MySQL

Plan/common/src/main/java/com/djrapitops/plan/db/access/transactions/init/RemoveDuplicateUserInfoTransaction.java

@@ -1,3 +1,19 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
 package com.djrapitops.plan.db.access.transactions.init;
 
 import com.djrapitops.plan.db.access.transactions.Transaction;
@@ -25,7 +41,10 @@ public class RemoveDuplicateUserInfoTransaction extends Transaction {
         execute(
                 "DELETE" + FROM + UserInfoTable.TABLE_NAME +
                         WHERE + COLUMN_ID +
-                        " NOT IN (" + STATEMENT_SELECT_DUPLICATE_IDS + ')'
+                        // Nested query here is required because MySQL limits update statements with nested queries:
+                        // The nested query creates a temporary table that bypasses the same table query-update limit.
+                        // Note: MySQL versions 5.6.7+ might optimize this nested query away leading to an exception.
+                        " NOT IN (" + SELECT + "id" + FROM + '(' + STATEMENT_SELECT_DUPLICATE_IDS + ") as ids)"
         );
     }
 }