SQL command line

Question

Hi, my friend wants from me to write two queries for him but really I don't know ,would you please help me? also there is a table with two column (String Telephone and BIGIN Charge). the sentences that I want to write a query for that:

one: Reduce the “Charge” for all Telephone numbers starting with ‘123’ by 30. two: Update all the Telephone numbers in the table by adding a ‘02’ in front of it.

thanks.

** I use MySQL**

Answer 1

Something like this:

 select charge - 30 from YourTable where Telephone like '123%'

or

 update YourTable set charge = charge - 30 where Telephone like '123%'

I'm in doubt whether reduce means update or select so I have added both.

 update YourTable set Telephone = '02' + Telephone

Hope it helps

Answer 2

You get the null pointer exception because stmt is null. Typically, you have to create stmt by using conn.createStatement(). conn is the java.sql.Connection object.