Menu

Articles

Delete Duplicate Rows in MySQL and Keep One Record

Preview duplicate rows, delete extras with a self-join, verify the result in an InnoDB transaction, and add a unique key to prevent repeats.

How to Check Whether a Table Exists in MySQL

Check for a MySQL table with SHOW TABLES or INFORMATION_SCHEMA, or create it safely with IF NOT EXISTS—without assuming the existing schema matches.

MySQL Error 1040: Too Many Connections

Recover from MySQL Error 1040 with an administrator connection, inspect sessions, and size application pools against max_connections.

MySQL Error 1042: Can't Get Hostname for Your Address

Troubleshoot MySQL Error 1042 by checking reverse DNS from the server, host_cache resolution counters, and client host matching.

MySQL Error 1043: Bad Handshake

Troubleshoot MySQL Error 1043 by checking classic port 3306 vs X Protocol 33060, server handshake counters, proxies, and TLS evidence.

MySQL Error 1054: Unknown Column

Fix MySQL Error 1054 by checking real column names, table aliases, SELECT alias scope, and derived-table output columns.

MySQL Error 1129: Host Is Blocked

Fix MySQL Error 1129 by inspecting host_cache and handshake errors, correcting the connection problem, then safely unblocking the client host.

MySQL Error 1130: Host Is Not Allowed to Connect

Fix MySQL Error 1130 by matching the client host to a MySQL user@host account and checking DNS, skip_name_resolve, and least-privilege grants.

MySQL Error 1203: Too Many User Connections

Fix MySQL Error 1203 by checking the affected user@host connection cap, shared application pools, and max_user_connections settings.

MySQL Error 1226: User Limit Reached

Fix MySQL Error 1226 by identifying the account’s hourly query, update, or connection quota, then correcting the workload or account limit.