Help with simple LIKE query...

Question

I have a person table, the person table has a field which has their interests... In a form they choose which interests they have i.e. swimming, tennis through checkboxes. What i don't get IS how do i create a query based on this? (for example one person likes swimming and the other tennis:
SELECT * from Person WHERE interests LIKE '%Swimming%Tennis%';
the above gives me 0 results any ideas?

Answer 1

You can avoid difficult application issues by enabling a more appropriate schema.
Here is a very basic schema that may or may not work for you, but I hope it will give you some ideas. I did not create any unique indexes in this sample, but both PERSON and INTEREST table would have a unique index created on them. The PERSON_INTEREST table would have a non-unique index created for it. I also included a query that shows how to correctly query against this schema. This is in Oracle syntax, but the DDL should be similar to whatever DBMS you are using, and the SQL should be the same.
I'll be honest, this might be overkill for what you are attempting, but if you plan on extending your project / assignment in anyway, you would be better off with a more complete schema. I hope it helps. Good luck on your project / assignment.
CREATE TABLE PERSON          (PERSON_ID NUMBER,   NAME_LAST VARCHAR2(20), NAME_FIRST VARCHAR2(20), EMAIL VARCHAR2(30));
CREATE TABLE INTEREST        (INTEREST_ID NUMBER, INTEREST_DESC VARCHAR2(20));
CREATE TABLE PERSON_INTEREST (PERSON_ID NUMBER,   INTEREST_ID NUMBER);
INSERT INTO PERSON VALUES(1, 'SMITH','JOHN','[email protected]');
INSERT INTO PERSON VALUES(2, 'JONES','FRED','[email protected]');
INSERT INTO PERSON VALUES(3, 'ANDERSON','TOM','[email protected]');
INSERT INTO PERSON VALUES(4, 'JACOBSEN','SAM','[email protected]');
INSERT INTO PERSON VALUES(5, 'PUCKETT','KIRBY','[email protected]');
INSERT INTO INTEREST VALUES (1,'TENNIS');
INSERT INTO INTEREST VALUES (2,'SWIMMING');
INSERT INTO INTEREST VALUES (3,'BOWLING');
INSERT INTO INTEREST VALUES (4,'TABLE TENNIS');
INSERT INTO INTEREST VALUES (5,'FISHING');
INSERT INTO PERSON_INTEREST VALUES (1,1);
INSERT INTO PERSON_INTEREST VALUES (1,3);
INSERT INTO PERSON_INTEREST VALUES (1,5);
INSERT INTO PERSON_INTEREST VALUES (2,2);
INSERT INTO PERSON_INTEREST VALUES (2,3);
INSERT INTO PERSON_INTEREST VALUES (3,1);
INSERT INTO PERSON_INTEREST VALUES (3,2);
INSERT INTO PERSON_INTEREST VALUES (4,2);
INSERT INTO PERSON_INTEREST VALUES (4,3);
INSERT INTO PERSON_INTEREST VALUES (5,4);
INSERT INTO PERSON_INTEREST VALUES (5,5);
// Find all the Interests for a Person
SELECT
   A.NAME_LAST,
   A.NAME_FIRST,
   B.INTEREST_DESC
FROM
   PERSON A,
   INTEREST B,
   PERSON_INTEREST C
WHERE
   A.NAME_LAST = 'SMITH'
   AND A.NAME_FIRST = 'JOHN'
   AND A.PERSON_ID = C.PERSON_ID
   AND B.INTEREST_ID = C.INTEREST_ID  
ORDER BY 3
NAME_LAST            NAME_FIRST           INTEREST_DESC
SMITH                JOHN                 BOWLING
SMITH                JOHN                 FISHING
SMITH                JOHN                 TENNIS
// Find all people who likes to swim and bowl
SELECT
   A.NAME_LAST,
   A.NAME_FIRST
FROM
   PERSON A,
   INTEREST B,
   PERSON_INTEREST C
WHERE
   B.INTEREST_DESC IN ('SWIMMING', 'BOWLING')
   AND B.INTEREST_ID = C.INTEREST_ID  
   AND A.PERSON_ID = C.PERSON_ID
GROUP BY
   A.NAME_LAST,
   A.NAME_FIRST
ORDER BY 1,2
NAME_LAST            NAME_FIRST
ANDERSON             TOM
JACOBSEN             SAM
JONES                FRED
SMITH                JOHN