PL/SQL ORA-01422 Error for SELECT INTO, Oracle Anonymous Block (NOVA Environment)

Question

Getting the following Error: ORA-01422: exact fetch returns more than requested number of rows ORA-6512

New to PL/SQL and although I KNOW this query should be conducted via standard SQL, I am trying to figure out how to accomplish this using PL/SQL.

I need the query to return the total number of SALES for customers with zip code '20636'

Here are the tables/input:

CREATE TABLE CUSTOMERS
(customerID     INT     PRIMARY KEY,
customerZip     VARCHAR(15) NOT NULL); 

CREATE TABLE SALES
(saleID         INT     PRIMARY KEY,
customerID      INT,
CONSTRAINT SALES_FK1 FOREIGN KEY (customerID) REFERENCES CUSTOMERS(customerID));

INSERT INTO CUSTOMERS (customerID, customerZIP) VALUES (1, '20636');
INSERT INTO CUSTOMERS (customerID, customerZIP) VALUES (2, '20619');
INSERT INTO CUSTOMERS (customerID, customerZIP) VALUES (3, '20650');
INSERT INTO CUSTOMERS (customerID, customerZIP) VALUES (4, '20670');
INSERT INTO CUSTOMERS (customerID, customerZIP) VALUES (5, '20636');

INSERT INTO SALES (saleID, customerID) VALUES (1, 1);
INSERT INTO SALES (saleID, customerID) VALUES (2, 2);
INSERT INTO SALES (saleID, customerID) VALUES (3, 3);
INSERT INTO SALES (saleID, customerID) VALUES (4, 4);
INSERT INTO SALES (saleID, customerID) VALUES (5, 5);

Here's the code that I have written for the PL/SQL anonymous block:

DECLARE
customerZip INTEGER;
totalSales INTEGER;
BEGIN
SELECT customerID INTO customerZip from CUSTOMERS where customerZip = '20636';
SELECT COUNT(*) INTO totalSales from SALES where customerID = customerZip;
DBMS_OUTPUT.put_line('We sold ' || totalSales || ' Cars to customers in Zip Code ' || customerZip ||'.');
END;
/

If I run this without having two customerZIP attributes set at '20636', it works fine. As soon as I enter more than one customer record with the zip code '20636', I get the error.

Can you please explain what I'm doing wrong here and how I can fix it? Thank you!

SQL Fiddle link if it helps: http://sqlfiddle.com/#!4/10fc1

Answer 1

You may use such a statement :

SQL> set serveroutput on;
SQL> DECLARE
  v_customerZip CUSTOMERS.customerZip%type:='20636';
  v_customerID  CUSTOMERS.customerID%type;
  totalSales    INTEGER:=0;
  Sales         INTEGER;
BEGIN
 for c in ( SELECT customerID from CUSTOMERS where customerZip = v_customerZip )
 loop
  v_customerID := c.customerID;
  SELECT COUNT(1) INTO Sales from SALES where customerID = v_customerID;
  totalSales := totalSales + Sales;
 end loop; 
  dbms_output.put_line('We sold ' || totalSales || ' Cars to customers in Zip Code ' || v_customerZip ||'.');
END;
/
We sold 2 Cars to customers in Zip Code 20636.

and change variable v_customerZip's value whatever you wish from declaration part.

Or you may create a procedure to accomplish this task :

SQL> CREATE OR REPLACE PROCEDURE GET_SALES( v_customerZip CUSTOMERS.customerZip%type ) IS
  v_customerID  CUSTOMERS.customerID%type;
  totalSales    INTEGER:=0;
  Sales         INTEGER;
BEGIN
 for c in ( SELECT customerID from CUSTOMERS where customerZip = v_customerZip )
 loop
  v_customerID := c.customerID;
  SELECT COUNT(1) INTO Sales from SALES where customerID = v_customerID;
  totalSales := totalSales + Sales;
 end loop; 
  dbms_output.put_line('We sold ' || totalSales || ' Cars to customers in Zip Code ' || v_customerZip ||'.');
END;
/
SQL> exec get_sales('&cZ');
Enter value for cz: 20636
We sold 2 Cars to customers in Zip Code 20636.