Form your initial insertion query, such as "INSERT INTO your_table (column1,column2) VALUES ('1','a');" Alter the query by adding a rule for what to do if a duplicate key is found, such as "INSERT ...

I’ve created a script that monitors a table in a SQL Server database. I’m only interested in one column in the table: TimeStamp. If the maximum (newest) value in TimeStamp is more than 30 ...