create table ranks (
rank varchar(20)
);
create table people (
name varchar(20)
);
insert into people values('Sam', 'Bob', 'Tim');
declare cursor c1 is (select substr(name, -1) from people)
begin
for i in c1
loop
update ranks
set rank = 'S'
where i = 'S';
end loop;
end;
Hello, I am trying to use the last letter of the people table to decide who gets the S rank, but it isn't working. I keep getting - expression is of wrong type - error. Please help.
Data model looks wrong. That should be only one table with two columns.
SQL> CREATE TABLE people
2 (
3 name VARCHAR2 (20),
4 RANK VARCHAR2 (1)
5 );
Table created.
SQL> INSERT INTO people (name) VALUES ('Sam');
1 row created.
SQL> INSERT INTO people (name) VALUES ('Bob');
1 row created.
SQL> INSERT INTO people (name) VALUES ('Tim');
1 row created.
SQL> COMMIT;
Commit complete.
SQL> SELECT * FROM people;
NAME RANK
-------------------- -----
Sam
Bob
Tim
SQL>
Then, you don't need PL/SQL - a simple UPDATE will do. However, code you posted doesn't make much sense either - substr(name, -1) selects the last letter; nobody has a name that ends with an S so - no rows will ever be updated (at least, not for sample data). That's why I modified it to use the 1st letter.
SQL> UPDATE people
2 SET RANK = 'S'
3 WHERE SUBSTR (name, 1, 1) = 'S';
1 row updated.
SQL> SELECT * FROM people;
NAME R
-------------------- -
Sam S
Bob
Tim
SQL>
If it has to be PL/SQL (because you're learning it), then you'd
SQL> ROLLBACK;
Rollback complete.
SQL> BEGIN
2 FOR cur_r IN (SELECT name FROM people)
3 LOOP
4 UPDATE people
5 SET RANK = 'S'
6 WHERE name = cur_r.name
7 AND SUBSTR (name, 1, 1) = 'S';
8 END LOOP;
9 END;
10 /
PL/SQL procedure successfully completed.
SQL> SELECT * FROM people;
NAME RANK
-------------------- ----
Sam S
Bob
Tim
SQL>
insert into people values('Sam', 'Bob', 'Tim');
Will fail as you only have one column and not three. You want to either use multiple inserts:
insert into people (name) values('Sam');
insert into people (name) values('Bob');
insert into people (name) values('Tim');
Or, use an INSERT ... SELECT ...
insert into people (name)
SELECT 'Sam' FROM DUAL UNION ALL
SELECT 'Bob' FROM DUAL UNION ALL
SELECT 'Tim' FROM DUAL;
Then you want something like:
begin
for i in (select substr(name, -1) AS last_character from people)
loop
update ranks
set rank = 'S'
where i.last_character = 'S';
end loop;
end;
/
But that can be simplified to get rid of the cursor and use a single UPDATE statement:
UPDATE ranks
SET rank = 'S'
WHERE EXISTS(
SELECT 1
FROM people
WHERE name LIKE '%S'
);
But neither of those will do anything as:
The ranks table contains zero rows.
None of the people have a name ending in S.
If you fix both of those then you will just end up updating every row in the ranks table as there is no relationship between a person and a rank.
db<>fiddle here
A simplified version of using cursors is to declare the cursor and then use it
multiple times if required later. This way opening similar dataset in multiple
cursors can be avoided. A good practice to develop when working on code
intensive procedures.
SQL> Declare
cur_people is SELECT name FROM people;
BEGIN
FOR cur_r IN cur_people
LOOP
UPDATE people
SET RANK = 'S'
WHERE name = cur_r.name
AND SUBSTR (name, 1, 1) = 'S';
END LOOP;
END;
/
I have a table with these columns (id,first_name,birth). I want to create a procedure that insert a new customer only if the id inserted doesn't exist in the table. If it already exist, then don't insert it. This is my code so far, but I got an error 'line 3 sql statement ignored'. Any idea? I need to use procedure and pl sql in oracle. Thanks!
CREATE OR REPLACE PROCEDURE add_emp(v_id IN int,
v_name IN varchar2,
v_bday IN date) IS
BEGIN
INSERT INTO Employees
(Id, First_name, Birth)
SELECT *
FROM (SELECT v_id, v_name, v_bday) AS tmp
WHERE NOT EXISTS (SELECT Id FROM Employees WHERE Id = v_id);
END;
/
DECLARE
m_id int := 3;
m_name varchar2 := 'John';
m_bday date := '16-Dec-1990';
BEGIN
add_cust(m_id, m_name, m_bday);
END;
/
Your procedure has some syntax issue which is fixed in following code:
CREATE OR REPLACE PROCEDURE ADD_EMP (
V_ID IN INT,
V_NAME IN VARCHAR2,
V_BDAY IN DATE
) IS
BEGIN
INSERT INTO EMPLOYEES (
ID,
FIRST_NAME,
BIRTH
)
SELECT V_ID,
V_NAME,
V_BDAY
FROM DUAL -- FROM clause was missing
WHERE NOT EXISTS (
SELECT ID
FROM EMPLOYEES
WHERE ID = V_ID
);
END;
/
Also, Your calling PL/SQL block has some issues which are corrected in the following code:
DECLARE
M_ID INT := 3;
M_NAME VARCHAR2(10) := 'John'; -- varchar2 must be declared with size
M_BDAY DATE := DATE '1990-12-16'; -- added date literal to convert string to date
BEGIN
ADD_CUST(M_ID, M_NAME, M_BDAY);
END;
/
In Oracle SELECT does not work without a FROM clause (other DBMS products are different). So you need to provide a table; you can use DUAL, which is a dummy table provided by Oracle which is guaranteed to return one row.
INSERT INTO Employees(Id,First_name,Birth)
SELECT v_id, v_name, v_bday
from dual
WHERE NOT EXISTS (
SELECT Id FROM Employees WHERE Id = v_id
);
Your INSERT statement would work with a slight change
CREATE OR REPLACE PROCEDURE add_emp(v_id Employees.Id%type,
v_name Employees.First_name%type,
v_bday Employees.Birth%type) IS
BEGIN
INSERT INTO Employees
(Id, First_name, Birth)
SELECT v_id, v_name, v_bday
FROM dual
WHERE NOT EXISTS (SELECT * FROM Employees WHERE Id = v_id);
END;
/
You can replace INSERT statement with MERGE as an alternative DML such as
MERGE INTO Employees e1
USING
(SELECT v_id AS id, v_name AS First_name, v_bday AS birth
FROM dual) e2
ON ( e1.id = e2.id )
WHEN MATCHED THEN UPDATE SET e1.First_name = e2.First_name,
e1.Birth = e2.Birth -- If you need to change for the matching case
WHEN NOT MATCHED THEN INSERT( e1.id, e1.First_name, e1.birth )
VALUES( e2.id, e2.First_name, e2.birth );
I know I didn't make it clear in the question title. Let me explain.
Say I have a Table SOURCE_TABLE with 1 column that looks like this:
Filter
------------------|
Name='John'
Surname = 'Smith'
Age = '25'
And I want to use this table as a filter. Like below:
SELECT * FROM TARGET_TABLE WHERE (SELECT FILTER FROM SOURCE_TABLE)
I heard maybe evaluate function could help me but to be honest I couldn't understand how.
Do you know any method that I can use a column as my filter source like above?
Edit1:
DECLARE
my_filter VARCHAR2(100);
my_query VARCHAR2(500);
BEGIN
my_query := 'SELECT FILTER FROM SOURCE_TABLE WHERE ROWNUM=1';
EXECUTE IMMEDIATE my_query INTO my_filter;
EXECUTE IMMEDIATE 'SELECT * FROM TARGET_TABLE WHERE '|| my_filter;
END;
#Sujitmohanty30 I have come up with the above after learning EXECUTE IMMEDIATE. But there is a problem I stumble upon. This needs to be dynamic regarding to the end result and i want to see the result of the select query at the end.
Let's say we have these 2 tables:
create table TARGET_TABLE(name varchar2(30), surname varchar2(30));
insert into TARGET_TABLE(name,surname) values ('John', 'Doe');
insert into TARGET_TABLE(name,surname) values ('Ann', 'Smith');
insert into TARGET_TABLE(name,surname) values ('Steven', 'Feuerstein');
insert into TARGET_TABLE(name,surname) values ('Steven', 'King');
commit;
create table SOURCE_TABLE(filter) as
select q'[name='John']' from dual union all
select q'[name='Ann']' from dual union all
select q'[name='Steven' and surname='King']' from dual union all
select q'[surname='Feuerstein']' from dual;
Then you can use xmltable and dbms_xmlgen.getXMLtype to get such rows dynamically:
https://dbfiddle.uk/?rdbms=oracle_18&fiddle=72abdf18b149cf30882cb4e1736c9c33
select *
from SOURCE_TABLE
, xmltable(
'/ROWSET/ROW'
passing dbms_xmlgen.getXMLtype('select * from TARGET_TABLE where '|| SOURCE_TABLE.filter)
columns
name varchar2(30) path 'NAME',
surname varchar2(30) path 'SURNAME'
) x;
Results:
FILTER NAME SURNAME
-------------------------------- ------------------------------ ------------------------------
name='John' John Doe
name='Ann' Ann Smith
name='Steven' and surname='King' Steven King
surname='Feuerstein' Steven Feuerstein
So I have been trying to find the best way to re-write a large chunk of SQL in plan script, in form of
WITH
A AS (...<SUB_QA>...),
B AS (...<SUB_QB>...),
C AS (...<SUB_QC>...),
...
SELECT ... FROM
A
LEFT JOIN B
LEFT JOIN C
LEFT JOIN ...
ON ....
into a FUNCTION. This is mainly to facilitate the reuse the same logic represented by that big chunk in multiple places.
Contraint 1: can only use RECORD instead of creating customized TYPE;
Contraint 2: have to keep the content of the those subqueries (e.g.
, etc) under WITH clause as they are, since each is
considerably complex.
So far, I only came up with the following, as a simplified example.
It involves putting the WITH clause in the cursor loop
But does it run the WITH clause in each loop, which would be a big worry in term of performance? When written in function form, and when I run it with SqlDeveloper's 'Explain Plan' function, it doesn't reveal much helpful information at all.
Is there better/cleaner/more performant way to do this?
SQL to create data:
--------PERSON table------------
DROP TABLE Test_Persons;
CREATE TABLE Test_Persons (
PersonID int,
LastName varchar2(255),
FirstName varchar2(255)
);
INSERT INTO Test_Persons
(PersonID,LastName,FirstName)
values(1,'LN_1','FN_1');
INSERT INTO Test_Persons
(PersonID,LastName,FirstName)
values(2,'LN_2','FN_2');
INSERT INTO Test_Persons
(PersonID,LastName,FirstName)
values(3,'LN_21','FN_2');
--------Salary table------------
DROP TABLE TEST_SALARY_A;
CREATE TABLE TEST_SALARY_A ( -- no 'OR REPLACE' for ORACLE
SalaryID int,
PersonID int,
Amount int,
Tax int,
Bank varchar2(20)
);
INSERT INTO TEST_SALARY_A
(SalaryID, PersonID, Amount, Tax, Bank)
VALUES
(1, 1, 1000, 300, 'BOA1');
INSERT INTO TEST_SALARY_A
(SalaryID, PersonID, Amount, Tax, Bank)
VALUES
(2, 2, 2000, 600, 'JP1');
INSERT INTO TEST_SALARY_A
(SalaryID, PersonID, Amount, Tax, Bank)
VALUES
(3, 3, 3000, 900, 'TD1');
--------Address table------------
DROP TABLE TEST_ADDRESS_A;
CREATE TABLE TEST_ADDRESS_A (
AddressID int,
PersonID int,
Address varchar2(255)
);
INSERT INTO TEST_ADDRESS_A
(AddressID, PersonID, Address)
VALUES
(1, 1, 'address1');
INSERT INTO TEST_ADDRESS_A
(AddressID, PersonID, Address)
VALUES
(2, 2, 'address2');
INSERT INTO TEST_ADDRESS_A
(AddressID, PersonID, Address)
VALUES
(3, 3, 'address3');
commit;
Original SQL in Chunk:
------------------Original--------------------
WITH
TEST_JOINED_1 AS (
SELECT
tps.PERSONID,
tps.LASTNAME,
tsd.ADDRESS
FROM TEST_PERSONS tps
LEFT JOIN TEST_ADDRESS_A tsd ON tps.personid = tsd.personid WHERE tps.LASTNAME = 'LN_1'
),
TEST_JOINED_2 AS (
SELECT
tps.PERSONID,
tsl.BANK,
tsl.TAX
FROM TEST_PERSONS tps
LEFT JOIN TEST_SALARY_A tsl ON tps.personid = tsl.personid WHERE tps.LASTNAME = 'LN_1'
)
SELECT tj1.PERSONID as tj1_ID, tj1.LASTNAME, tj1.ADDRESS, tj2.PERSONID as tj2_ID, tj2.BANK, tj2.TAX
FROM TEST_JOINED_1 tj1
LEFT JOIN TEST_JOINED_2 tj2 ON tj1.PERSONID = tj2.PERSONID
WHERE tj1.LASTNAME = 'LN_1';
Rewrite in FUNCTION:
------------------Rewritten in functions with ------------------
------------------Contraint 1: can only use RECORD instead of creating customized TYPE;------------
------------------Contraint 2: have to keep the content of the two subqueries under WITH clause exactly as it is --------------
CREATE OR REPLACE PACKAGE MY_JOIN_TEST_SP_PACKAGE_3 AS
TYPE join_record_type IS RECORD(
PersonID1 int,
LastName varchar2(255),
Address varchar2(255),
PersonID2 int,
Bank varchar2(20),
Tax int
);
TYPE join_record_table_type IS TABLE OF join_record_type;
FUNCTION get_joined_data(last_name VARCHAR2)
RETURN join_record_table_type
PIPELINED;
END;
/
CREATE OR REPLACE PACKAGE BODY MY_JOIN_TEST_SP_PACKAGE_3 AS
FUNCTION get_joined_data(last_name VARCHAR2)
RETURN join_record_table_type
PIPELINED
AS
join_record join_record_type;
BEGIN
FOR x IN (
-------------------start - WITH clause -- does this run for every RECORD x in the loop??? -----------------------
WITH
TEST_JOINED_1 AS (
SELECT
tps.PERSONID,
tps.LASTNAME,
tsd.ADDRESS
FROM TEST_PERSONS tps
LEFT JOIN TEST_ADDRESS_A tsd ON tps.personid = tsd.personid WHERE tps.LASTNAME = last_name
),
TEST_JOINED_2 AS (
SELECT
tps.PERSONID,
tsl.BANK,
tsl.TAX
FROM TEST_PERSONS tps
LEFT JOIN TEST_SALARY_A tsl ON tps.personid = tsl.personid WHERE tps.LASTNAME = last_name
)
-------------------end - WITH clause -------------------
-------------------start - main select-----------------------
SELECT tj1.PERSONID as tj1_ID, tj1.LASTNAME, tj1.ADDRESS, tj2.PERSONID as tj2_ID, tj2.BANK, tj2.TAX
FROM TEST_JOINED_1 tj1
LEFT JOIN TEST_JOINED_2 tj2 ON tj1.PERSONID = tj2.PERSONID
WHERE tj1.LASTNAME = last_name
-------------------end - main select--------------------------
)
LOOP
SELECT x.tj1_ID, x.LASTNAME, x.ADDRESS, x.tj2_ID, x.BANK, x.TAX
INTO join_record
FROM DUAL;
PIPE ROW (join_record);
END LOOP;
END;
END; -- END of CREATE
/
select * from table(MY_JOIN_TEST_SP_PACKAGE_3.get_joined_data('LN_1'));
EDITED: modified example code to have variable in the WITH clause
----------------------Create GLOBAL TEMPORARY TABLE -------------------------
DROP TABLE my_global_temp_table;
CREATE GLOBAL TEMPORARY TABLE my_global_temp_table (
PersonID int,
LastName varchar2(255),
Address varchar2(255),
Bank varchar2(20)
)
ON COMMIT DELETE ROWS;
----------------------Create PACKAGE AND FUNCTION -------------------------
CREATE OR REPLACE PACKAGE MY_JOIN_TEST_SP_PACKAGE_3 AS
TYPE join_record_type IS RECORD(
PersonID int,
LastName varchar2(255),
Address varchar2(255),
Bank varchar2(20)
);
TYPE join_record_table_type IS TABLE OF join_record_type;
FUNCTION get_joined_data(last_name VARCHAR2)
RETURN join_record_table_type
PIPELINED;
END;
/
CREATE OR REPLACE PACKAGE BODY MY_JOIN_TEST_SP_PACKAGE_3 AS
FUNCTION get_joined_data(last_name VARCHAR2)
RETURN join_record_table_type
PIPELINED
AS
join_record join_record_type;
BEGIN
--------------------use GLOBAL TEMPORARY TABLE-------------------------
INSERT INTO my_global_temp_table
-------------------start - WITH ... SELECT ... clause -- does this run for every RECORD x in the loop??? -----------------------
WITH
TEST_JOINED_1 AS (
SELECT
tps.PERSONID,
tps.LASTNAME,
tsd.ADDRESS
FROM TEST_PERSONS tps
LEFT JOIN TEST_ADDRESS_A tsd ON tps.personid = tsd.personid
WHERE tps.LASTNAME = last_name
)
SELECT tj1.PERSONID, tj1.LASTNAME, tj1.ADDRESS, ts.BANK
FROM TEST_JOINED_1 tj1
LEFT JOIN TEST_SALARY_A ts ON tj1.PERSONID = ts.PERSONID
WHERE tj1.LASTNAME = last_name;
-------------------end - WITH ... SELECT ... clause --
FOR x IN (
SELECT * FROM my_global_temp_table
)
LOOP
SELECT x.PERSONID, x.LASTNAME, x.ADDRESS, x.BANK
INTO join_record
FROM DUAL;
PIPE ROW (join_record);
END LOOP;
END;
END; -- END of CREATE
/
--------------------Call the FUNCTION-------------------------
select * from table(MY_JOIN_TEST_SP_PACKAGE_3.get_joined_data('LN_1'));
EDITED: following #Littefoot suggestion, try out using CREATE GLOBAL TEMP table but giving out '17/21 PL/SQL: ORA-00936: missing expression'. I am not sure why?
EDITED: Corrected the Insert syntax, but will get error 'ORA-14551: cannot perform a DML operation inside a query', I believe that this is because I called the function that contains that Insert from a SELECT
If you are not using variables and other pl sql constructs, I would suggest you break with clauses in the form of a table or materialize view. In this way you don't need to take risk of rewriting the logic of query in pl sql block and missing something.
I would suggest using materialize view advantage of materialize view over the table is that you don't need to drop table next time you load data and also you can use nologging with materialized view.No logging makes it very fast.
It will be very fast and have minimum risk.
Thanks
Bhanu Yadav
As there's nothing dynamic in the WITH factoring clause (i.e. you don't use variables - at least, I didn't notice any), I'd suggest you to create a view (based on that WITH) and use it whenever needed.
If the real query is really complex and takes time to execute, you could create a global temporary table (GTT), most probably choosing to keep its data during the session (ON COMMIT PRESERVE ROWS) properly index it and store view (or WITH's) contents in there. Then you'd use the GTT in your code
Although, Oracle will keep date returned by a query in memory so you might even have to really "execute" it once, but the memory isn't unlimited so ... test it, compare results you get, pick the one that seems to be the best.
To me, the GTT idea sounds promising, but without actual information it is difficult to decide.
[EDIT, about GTT]
Oracle's "Global temporary table" is, actually, "local" from your point if view (note that, if you're on 18c (I don't think you are, though) you can create a private temporary table). You create it once, using the create global temporary table .... Data you insert into it is visible ONLY to you, nobody else; it is restricted to your own transaction (if it is created with the ON COMMIT DELETE ROWS) or session (ON COMMIT PRESERVE ROWS). Pick the one that suits you best.
What does it mean? It means that you'd create the GTT once, providing column list and their datatypes. Every user, that uses your procedure, would insert its own data set into it (you'd use a query with the LAST NAME parameter, as you said) and use it throughout the transaction (or session). Many users can do that at the same time, but - as I've said - everyone would see only its own data.
Here's the pseudocode:
-- create table once. Do NOT create it, drop it, create again tomorrow, drop ...
-- Create it once, use it many times.
create global temporary table gtt_my_data
(id number,
c_name varchar2(20), ...
)
on commit preserve rows;
create index i1_gmd_id on gtt_my_data (id);
-- your procedure
procedure p_myproc (par_last_name in varchar2) is
begin
insert into gtt_my_data (id, c_name, ...)
select id, c_name, ...
from some_table join some_other_table ...
where some_table.last_name = par_last_name;
-- now, do whatever you do. When you need to fetch data from the GTT, do so
select ... into ...
from table_x join gtt_my_data on ...
update ... set some_column = (select another_column
from table_y join gtt_my_data on ...
)
end;
Once you're done: if you end the session, data will be removed from the GTT. If you want, you can do it manually (either delete or truncate its contents).
[EDIT #2: INSERT INTO A GTT]
Insert is wrong; you don't insert values, but something like this:
INSERT INTO my_global_temp_table
WITH test_joined_1 AS
(SELECT tps.personid,
tps.lastname,
tsd.address
FROM test_persons tps
LEFT JOIN test_address_a tsd ON tps.personid = tsd.personid
WHERE tps.lastname = last_name
)
SELECT tj1.personid,
tj1.lastname,
tj1.address,
ts.bank
FROM test_joined_1 tj1
LEFT JOIN test_salary_a ts ON tj1.personid = ts.personid
WHERE tj1.lastname = last_name;
Simplified, on Scott's schema:
SQL> create table test (empno number, deptno number);
Table created.
SQL> insert into test (empno, deptno)
2 with temp as
3 (select empno, deptno from emp)
4 select t.empno, t.deptno
5 from temp t join dept d on d.deptno = t.deptno
6 where d.deptno = 10;
3 rows created.
SQL>
I have a TYPE called Employee which has an ORDER method which takes an Employee as a parameter. I have created a table of Employee and inserted some data. I am trying to test this ORDER method using SELECT however i am having difficulty satisfying the parameter. here is my code
CREATE OR REPLACE TYPE Employee AS OBJECT(
EmpID VARCHAR(15),
eName VARCHAR(30),
ePhone NUMBER,
eAddress VARCHAR(15),
ePosition VARCHAR(15),
eHireDt DATE,
salary NUMBER,
ORDER MEMBER FUNCTION orderSalary (e Employee) RETURN NUMBER)
NOT FINAL;
/
CREATE OR REPLACE TYPE BODY Employee AS
ORDER MEMBER FUNCTION orderSalary(e Employee) return number IS
BEGIN
IF(self.salary > e.salary) then
return(1);
ELSIF (self.salary < e.salary) then
return(-1);
ELSE
return(0);
END IF;
END;
END;
/
CREATE TABLE Emp OF Employee (EmpID PRIMARY KEY)
OBJECT IDENTIFIER PRIMARY KEY;
insert into Emp values('001','kabir',6477732272,'Pharmacy','clerk','2016-03-28',2000);
Here is the line that is giving me trouble:
SELECT p.orderSalary(Employee s) FROM Emp p;
All i need to do is test this method to make sure it works, is there any way i can create an instance of Employee to use as a parameter, or perhaps take a row from the Emp table? Thanks!
SELECT p.orderSalary( VALUE( p ) ) FROM Emp p;
Or:
SELECT p.orderSalary( DEREF( REF( p ) ) ) FROM Emp p;
Or:
SET SERVEROUTPUT ON;
DECLARE
e1 EMPLOYEE := NEW EMPLOYEE('001','kabir',6477732272,'Pharmacy','clerk',DATE '2016-03-28',2000);
e2 EMPLOYEE := NEW EMPLOYEE('002','bob',1234567890,'Library','assistant',DATE '2016-03-07',1000);
BEGIN
DBMS_OUTPUT.PUT_LINE( e1.orderSalary( e2 ) );
END;
/
Update - Select different rows:
insert into Emp values('001','kabir',6477732272,'Pharmacy','clerk','2016-03-28',2000);
insert into Emp values('002','bob',1234567890,'Library','assistant',DATE '2016-03-07',1000);
SELECT e1.ename AS name1,
e2.ename AS name2,
e1.orderSalary( VALUE( e2 ) )
FROM Emp e1
CROSS JOIN Emp e2;
Outputs:
NAME1 NAME2 E1.ORDERSALARY(VALUE(E2))
------ ------ -------------------------
kabir kabir 0
kabir bob 1
bob kabir -1
bob bob 0