How can I delete multiple rows in two tables in SQL?
The syntax also supports deleting rows from multiple tables at once. To delete rows from both tables where there are matching id values, name them both after the DELETE keyword: DELETE t1, t2 FROM t1 INNER JOIN t2 ON t1.id = t2.id; What if you want to delete nonmatching rows?
How do you delete common records from two tables?
HAVING COUNT(*) > 1;
- In the output above, we have two duplicate records with ID 1 and 3.
- To remove this data, replace the first Select with the SQL delete statement as per the following query.
- SQL delete duplicate Rows using Common Table Expressions (CTE)
- We can remove the duplicate rows using the following CTE.
How to delete multiple rows from different tables in single query?
For deleting records from multiple tables: You could define Foreign Key constraints (which you have defined as EventID) for the other tables that reference the master table’s ID with ON DELETE CASCADE. This would cause the related rows in those tables to be deleted. This is the least programming model, is part of the SQL standard, etc.
How to delete a row from a T2 table?
The following syntax illustrates how to use DELETE statement with LEFT JOIN clause to delete rows from T1 table that does not have corresponding rows in the T2 table: DELETE T1 FROM T1 LEFT JOIN T2 ON T1.key = T2.key WHERE T2.key IS NULL; Note that we only put T1 table after the DELETE keyword, not both T1 and T2 tables like we did with
How to delete rows from a master table?
Specify foreign key for the details tables which references to the primary key of master and set Delete rule = Cascade . Now when u delete a record from the master table all other details table record based on the deleting rows primary key value, will be deleted automatically.
When to use left join in MySQL to delete rows?
MySQL DELETE JOIN with LEFT JOIN. We often use the LEFT JOIN clause in the SELECT statement to find rows in the left table that have or don’t have matching rows in the right table. We can also use the LEFT JOIN clause in the DELETE statement to delete rows in a table (left table) that does not have matching rows in another table (right table).