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Databases

SQL that works: SELECT and JOIN, schema changes, users and GRANT, backups and indexes — for PostgreSQL, MySQL, SQL Server, Oracle and SQLite.

ERROR 1045 (28000): Access denied for user
Databases

MySQL ERROR 1045 (28000): Access denied for user — find which part is wrong

Fix MySQL "ERROR 1045 Access denied for user": check the user@host account, the password, socket vs TCP, option files, and Docker init passwords.

Beginner · 5 min read

duplicate key value
Databases

PostgreSQL "duplicate key value violates unique constraint": causes and fixes

Fix "duplicate key value violates unique constraint" in PostgreSQL: tell a real duplicate from a sequence that is out of sync, and fix both safely.

Intermediate · 4 min read

permission denied for table
Databases

PostgreSQL "permission denied for table": causes and fixes

Fix "ERROR: permission denied for table" in PostgreSQL: check what a role can do, grant the right privileges, and fix the schema, sequence and future-table cases.

Intermediate · 4 min read