Pick exact records - sql

Question

INSERT INTO filerecord (fname,
lname,
transdate,
memberid)
VALUES ('tyler',
'smith',
TO_DATE ('07/01/2016', 'mm/dd/yyyy'),
'111');
I get the following result:
fname lname email
fernando hernandez fh#yahoo.com
fernando hernandez ts#hotmail.com
IT should not display Tyler Smith's Name & Email due to the transdate clause. I am looking for someone to get me only the Fernando Result.
I cannot change the structure of the tables.

Answer 1

You are getting a Cartesian product.
You have two entries with memberid = '111' in both tables, so this condition
AND b.memberid = e.memberid
filters you down to 4 rows --
one with Tyler Smith joined to Tyler Smith's email
one with Fernando Hernandez joined to Fernando Hernandez's e-mail,
one with Tyler Smith joined to Fernando Hernandez's email and
one with Fernando Hernandez joined to Tyler Smith's email
Then, this condition:
AND b.transdate >= TO_DATE ('07/02/2016', 'mm/dd/yyyy');
excludes two of those but not the other two.
You need a better data model and/or a more exact way to join your two tables.
In general, anytime you join two tables, one of the tables should have all of its primary key columns specified to avoid this type of error. (There are exceptions to that, as always).

Answer 2

It is not. I just created a new table and checked.
Table member
create table member (programid varchar(10), memberid int, fname varchar(10), lname varchar(10), email varchar(25))
Content
+-----------+----------+----------+-----------+----------------+
| PROGRAMID | MEMBERID | FNAME | LNAME | EMAIL |
+-----------+----------+----------+-----------+----------------+
| BLUE | 111 | tyler | smith | ts#hotmail.com |
| GREEN | 111 | fernando | hernandez | fh#yahoo.com |
+-----------+----------+----------+-----------+----------------+
Table filerecord
create table filerecord (fname varchar(10), lname varchar(10), transdate date, memberid int);
Content
+-------+-------+-----------+----------+
| FNAME | LNAME | TRANSDATE | MEMBERID |
+-------+-------+-----------+----------+
| tyler | smith | 7/1/2016 | 111 |
+-------+-------+-----------+----------+
Last Query
SELECT b.fname, b.lname, e.email
FROM filerecord b, member e
WHERE b.memberid IN ('111')
AND b.memberid = e.memberid
AND b.transdate >= TO_DATE ('07/02/2016', 'mm/dd/yyyy');
Result -
no rows selected.

Answer 3

Since memberid is not a unique identifier, there no reason to expect good things from a join condition like b.memberid = e.memberid.
Instead, you seem to suggest (or believe) that (memberid, fname, lname) should be a unique identifier. So, use it in the join condition:
... WHERE ... AND b.memberid = e.memberid
AND b.fname = e.fname
AND b.lname = e.lname
...
Like so:
SQL> SELECT b.fname, b.lname, e.email
2 FROM filerecord b, member e
3 WHERE b.memberid IN ('111')
4 AND b.memberid = e.memberid
5 AND b.fname = e.fname
6 AND b.lname = e.lname
7 AND b.transdate >= TO_DATE ('07/02/2016', 'mm/dd/yyyy');
FNAME LNAME EMAIL
-------------------- -------------------- --------------------
fernando hernandez fh#yahoo.com
1 row selected.