#MySQL删除数据

-- Delete single row

-- Delete multiple rows

-- Delete with multiple conditions

-- Delete all rows

-- Delete all rows (DANGEROUS!)

-- Better: Use TRUNCATE for better performance

-- Delete based on ID

-- Delete with pattern

-- Delete with subquery

-- Delete with EXISTS

-- Delete with ORDER BY

-- Delete oldest 100 records

-- Delete with ORDER BY and LIMIT

-- Delete with INNER JOIN

-- Delete with LEFT JOIN

-- Delete with multiple tables

-- Add soft delete column

-- Create index for performance

-- Instead of DELETE, use UPDATE

-- Query with soft delete filter

-- Include deleted records

-- Include deleted with filter

-- Data preserved for audit

-- Recovery possible

-- No foreign key issues
-- Related records remain intact

-- Delete in chunks to avoid locking
-- Repeat until all deleted

-- Use stored procedure
    
        

-- DANGEROUS: Deletes all rows

-- SAFE: With WHERE clause

-- Create backup

-- Or use transaction
-- Verify
-- COMMIT; or ROLLBACK;

-- First, verify what will be deleted

-- Then delete

-- Delete records older than 1 year

-- Delete records older than specific date

-- Delete duplicate records

-- Delete orphaned records

-- Delete with cascade simulation

-- Delete old cart items

-- Foreign key constraint error
-- Error: Cannot delete or update a parent row
-- Solution: Delete child records first or use ON DELETE CASCADE

-- Lock wait timeout
-- Error: Lock wait timeout exceeded
-- Solution: Delete in smaller batches

-- Table is read only
-- Error: Table is read only
-- Solution: Check table engine and permissions

-- Check affected rows

-- Show tables using row

-- Check locks