For sorting we use order by clause in select statement. This is used to sort data in ascending order or descending order.
To group data based on perticulr column we use groupby clause.
Both are used to get distinct values.
Insert/Update/Delete :- 3
Row Level/Statement Level:-2
This is called dynamic SQL. An example would be:
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select ?drop user ?||username||? cascade;? from dba_users
where username not in ("SYS?,?SYSTEM?);
Essentially you are looking to see that they know to include a command (in this case DROP USER...CASCADE;) and that you need to concatenate using the ?||? the values selected from the database.
SIGN (a): Returns 1 if a is positive or if a is 0, and -1 if a is less than 0.
A scrollable cursor, however, can move forward and backward, and can seek any desired record in the cursor. Such operations are common in applications that present results sets in scrolling windows. With a scrollable cursor, application developers do not need to create and manage their own buffer for the records.