ORACLE-34-IF statement, Case statement, loop Loop, while loop, for loop

One, if statement

In PL/SQL, keywords such as if, then, else, elsif, endif are used to perform conditional logic

Syntax format:

if conditions 1 Then

Statement 1

elsif conditions 2 Then

Statement 2

Else

Statement 3

End If;

Example 1: Practice If structure

Solution: Note the program in:

Second, Case statement

Syntax structure:

Case variables

when value 1 Then Statement 1;

when value 2 Then Statement 2;

when value 3 Then Statement 3;

......

when value N Then Statement N;

[Else statement ]

End case;

Where [else statements] can be written without writing.

Example 2: Practice Case statements

Solution: Note the program in:

Example 3: Practice Case statements

Solution: The current time of the output is the day of the week, first look at the current system time is the days of the week:

where To_char (sysdate, ' d ') is the current system time format, only display days, Oracle because it is a foreigner developed database system, so the 1th day of the week is Sunday, the 2nd day is Monday, ..., the 7th day is Saturday, so the program is as follows:

Third, circulation

Syntax format for 1.LOOP loops :

Loop

Looping statements

End Loop;

Like what:

Counter: = 0;

Loop

Counter: = counter + 1;

Exit when counter = 5;

End Loop;

Example 4: practicing loop loops

Solution: Note the program in:

If you find no output to the console, you can add the code as follows :

Output Result:

2.WHILE loop syntax format:

while conditions Loop

Statement

End Loop

Like what:

Counter: = 0;

While counter < 6 Loop

Counter: = Counter +1;

End Loop;

Example 5: practicing while loops

Solution: Note the program in:

3.FOR loop syntax format

for variable in [revers] variable initial value: Variable Loop End value loop

Statement

End Loop;

Like what:

for i in 1..10 loop

Dbms_output.put_line (' i = ' + i);

End Loop;

Example 6: Practice for loop

Solution: Note the program in:

Example 7: Show 99 multiplication table

Solution: Note the program in:

where Dbms_out.put () is the output statement but does not wrap, if Dbms_output.put_line () is the output statement and wraps, so the 7th line prints null after the end of the inner loop, in fact it is a newline.

Example 8: Write a PL/SQL program, put Sno,sname in the Query student table into the record table variable, and print the data from the record table variable.

Solution: Note the program in:

The 6th line is the record in the T_record to the record table T_tab, that is, T_record in the ID and name, then there are t_tab.

ORACLE-34-IF statement, Case statement, loop Loop, while loop, for loop