Which two are true about dropping columns from a table?

You want to write a query that prompts for two column names and the WHERE condition each time it is executed in a session but only prompts for the table name the first time it is executed.
The variables used in your query are never undefined in your session?
Which query can be used?

View the exhibit and examine the descriptions of the DEPTand LOCATIONStables.

You want to update the CITYcolumn of the DEPTtable for all the rows with the corresponding value in the CITYcolumn of the LOCATIONStable for each department.
Which SQL statement would you execute to accomplish the task?
UPDATE dept d

Examine this SQL statement:

Which two are true?

Examine this statement:

On which two columns of the table will an index be created automatically?