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#cleanup

Commands grouped around the same concept, pattern, or recurring problem.

4 commands with this tag Browse related patterns quickly
intermediate updating MySQL MariaDB SQL Server PostgreSQL SQLite

Convert Blank Strings To NULL

Normalize empty or whitespace-only text values to `NULL` with `NULLIF(TRIM(...), '')`.

advanced deduplication MySQL MariaDB SQL Server PostgreSQL SQLite

Delete Duplicate Rows While Keeping One

Use `ROW_NUMBER()` to identify duplicate rows and delete every copy except the one you want to keep.

advanced deleting MySQL MariaDB SQL Server PostgreSQL SQLite

Delete Orphaned Child Rows

Remove child rows that reference missing parent rows before enforcing referential integrity.

beginner string-processing MySQL MariaDB SQL Server PostgreSQL SQLite

Trim Whitespace From Text

Remove leading and trailing whitespace from string values with `TRIM`.