Oracle PL/SQL/PL SQL/Variable
Содержание
Define variable and use it in SQL statement in PL/SQL
<source lang="sql">
SQL> SQL> CREATE TABLE session (
2 department CHAR(3), 3 course NUMBER(3), 4 description VARCHAR2(2000), 5 max_lecturer NUMBER(3), 6 current_lecturer NUMBER(3), 7 num_credits NUMBER(1), 8 room_id NUMBER(5) 9 );
Table created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 101, "History 101", 30, 11, 4, 20000);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 301, "History 301", 30, 0, 4, 20004);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 101, "Computer Science 101", 50, 0, 4, 20001);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 203, "Economics 203", 15, 0, 3, 20002);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 102, "Computer Science 102", 35, 3, 4, 20003);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 410, "Music 410", 5, 4, 3, 20005);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 101, "Economics 101", 50, 0, 4, 20007);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("NUT", 307, "Nutrition 307", 20, 2, 4, 20008);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 100, "Music 100", 100, 0, 3, NULL);
1 row created. SQL> SQL> select * from session; DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
HIS 101.00 History 101
30.00 11.00 4.00 ########
HIS 301.00 History 301
30.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
CS 101.00 Computer Science 101
50.00 .00 4.00 ########
ECN 203.00 Economics 203 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
15.00 .00 3.00 ########
CS 102.00 Computer Science 102
35.00 3.00 4.00 ########
MUS 410.00 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
Music 410
5.00 4.00 3.00 ########
ECN 101.00 Economics 101
50.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
NUT 307.00 Nutrition 307
20.00 2.00 4.00 ########
MUS 100.00 Music 100
100.00 .00 3.00
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
9 rows selected. SQL> SQL> SQL> SQL> DECLARE
2 v_Department VARCHAR2(3); 3 BEGIN 4 v_Department := "CS"; 5 DELETE FROM session 6 WHERE department = v_Department; 7 END; 8 /
PL/SQL procedure successfully completed. SQL> SQL> SQL> select * from session; DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
HIS 101.00 History 101
30.00 11.00 4.00 ########
HIS 301.00 History 301
30.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
CS 101.00 Computer Science 101
50.00 .00 4.00 ########
ECN 203.00 Economics 203 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
15.00 .00 3.00 ########
CS 102.00 Computer Science 102
35.00 3.00 4.00 ########
MUS 410.00 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
Music 410
5.00 4.00 3.00 ########
ECN 101.00 Economics 101
50.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
NUT 307.00 Nutrition 307
20.00 2.00 4.00 ########
MUS 100.00 Music 100
100.00 .00 3.00
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
9 rows selected. SQL> SQL> drop table session; Table dropped. SQL>
</source>
Use block name to reference a variable name
<source lang="sql">
SQL> SQL> SQL> CREATE TABLE session (
2 department CHAR(3), 3 course NUMBER(3), 4 description VARCHAR2(2000), 5 max_lecturer NUMBER(3), 6 current_lecturer NUMBER(3), 7 num_credits NUMBER(1), 8 room_id NUMBER(5) 9 );
Table created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 101, "History 101", 30, 11, 4, 20000);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 301, "History 301", 30, 0, 4, 20004);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 101, "Computer Science 101", 50, 0, 4, 20001);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 203, "Economics 203", 15, 0, 3, 20002);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 102, "Computer Science 102", 35, 3, 4, 20003);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 410, "Music 410", 5, 4, 3, 20005);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 101, "Economics 101", 50, 0, 4, 20007);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("NUT", 307, "Nutrition 307", 20, 2, 4, 20008);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 100, "Music 100", 100, 0, 3, NULL);
1 row created. SQL> SQL> select * from session; DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
HIS 101.00 History 101
30.00 11.00 4.00 ########
HIS 301.00 History 301
30.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
CS 101.00 Computer Science 101
50.00 .00 4.00 ########
ECN 203.00 Economics 203 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
15.00 .00 3.00 ########
CS 102.00 Computer Science 102
35.00 3.00 4.00 ########
MUS 410.00 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
Music 410
5.00 4.00 3.00 ########
ECN 101.00 Economics 101
50.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
NUT 307.00 Nutrition 307
20.00 2.00 4.00 ########
MUS 100.00 Music 100
100.00 .00 3.00
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
9 rows selected. SQL> SQL> SQL> <<l_DeleteBlock>>
2 DECLARE 3 Department CHAR(3); 4 BEGIN 5 Department := "CS"; 6 DELETE FROM session 7 WHERE department = l_DeleteBlock.Department; 8 END; 9 /
PL/SQL procedure successfully completed. SQL> SQL> SQL> select * from session; DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
HIS 101.00 History 101
30.00 11.00 4.00 ########
HIS 301.00 History 301
30.00 .00 4.00 ########
DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
ECN 203.00 Economics 203
15.00 .00 3.00 ########
MUS 410.00 Music 410 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
5.00 4.00 3.00 ########
ECN 101.00 Economics 101
50.00 .00 4.00 ########
NUT 307.00 DEP COURSE --- -------- DESCRIPTION
MAX_LECTURER CURRENT_LECTURER NUM_CREDITS ROOM_ID
---------------- ----------- --------
Nutrition 307
20.00 2.00 4.00 ########
MUS 100.00 Music 100
100.00 .00 3.00
7 rows selected. SQL> SQL> drop table session; Table dropped. SQL> SQL>
</source>
Use VARIABLE command to define variable
<source lang="sql">
SQL> SQL> -- Typing the VARIABLE command with no arguments provides a list of all variables created with the SQL> -- variable command: SQL> SQL> VARIABLE my_student NUMBER; SQL> SQL> VARIABLE variable my_student datatype NUMBER SQL>
</source>
Variable command: define a variable
<source lang="sql">
SQL> SQL> SQL> -- Print command SQL> SQL> SQL> VARIABLE g_result VARCHAR2(100) SQL> BEGIN
2 :g_result :="Hello"; 3 END; 4 /
PL/SQL procedure successfully completed. SQL> SQL> PRINT g_result G_RESULT
Hello SQL> SQL>
</source>
