P.Salmon questions

P.Salmon answers

• How to use functions in generated columns?
• How to pivot tables in MySQL
• Why does COUNT() show only one row of table?
• MySQL: Group by only connected rows
• The difference in the work of two similar queries with GROUP BY clause WITH ROLLUP in MariaDB
• Matching debit with credit per transaction in mysql or with better algothrim?
• I want to to find a way to get my appropriate result in 1 mysql query
• mysql - INSERT SELECT WHERE NOT EXISTS on empty table