SQL Query Error - sql-server

Question

Please check the SQL schema and query on SQL Fiddle
I'm getting repetitive records with NULL values, if anyone can rectify the problem.
Regards
This is what I am getting:
| MEM_ID | MEM_EMAIL | GENDER | EDUCATION | PROFESSION |
|--------|----------------|--------|-----------|-------------|
| 1 | it#email.com | Male | (null) | (null) |
| 1 | it#email.com | (null) | Graduate | (null) |
| 1 | it#email.com | (null) | (null) | Engineer |
| 2 | info#email.com | Female | (null) | (null) |
| 2 | info#email.com | (null) | Graduate | (null) |
| 2 | info#email.com | (null) | (null) | Not Working |
but I need
| MEM_ID | MEM_EMAIL | GENDER | EDUCATION | PROFESSION |
|--------|----------------|--------|-----------|-------------|
| 1 | it#email.com | Male | Graduate | Engineer |
| 2 | info#email.com | Female | Graduate | Not Working |
|

Answer 1

Ah yes, the famous Inner-Platform effect, where you try to implement relations by creating "attribute-value" tables and assigning magic strings for data types and values, then try to retrieve values with massive self-joins at runtime.
Only madness lies down this road. SQL already includes features for enforcing key values and referential integrity; don't try to implement this yourself. It's especially frustrating because your schema is actually quite simple:
CREATE TABLE [dbo].Member(
ID INT PRIMARY KEY,
Email Varchar(50) NOT NULL,
GenderID INT NOT NULL,
EducationID INT,
ProfessionID INT
)
CREATE TABLE [dbo].Gender(
GenderID INT PRIMARY KEY,
GenderName Varchar(50) NOT NULL
)
CREATE TABLE [dbo].Education(
EducationID INT PRIMARY KEY,
EducationName Varchar(50) NOT NULL
)
CREATE TABLE [dbo].Profession(
ProfessionID INT PRIMARY KEY,
ProfessionName Varchar(50) NOT NULL
)
Assign your magic values to Gender, Education, and Profession rows and assign their IDs to Member. You can perform full lookups with a simple:
SELECT ID, Email, GenderName, EducationName, ProfessionName
FROM Member m
JOIN Gender g ON g.GenderID=m.GenderID
LEFT JOIN Education e ON e.EducationID=m.EducationID
LEFT JOIN Profession p ON p.ProfessionID=m.ProfessionID
WHERE ...
You want to enforce values? Make the Member columns NOT NULL. Want to allow, say, only a single instance of each Education row per member? Foreign-key constraints already support this, no need to invent your own query language.

Answer 2

I think you are basically trying to do a pivot on your data. This is one way to accomplish that.
SELECT M.mem_Id,
M.mem_email,
[Gender] = (select max( A.att_value)
from tbl_attributes A
inner join tbl_mem_att_values MAV
on MAV.att_id = A.att_id
inner join tbl_types T
on T.type_id = A.type_id
where T.type_name = 'Gender'
and MAV.mem_Id = M.mem_Id),
[Education] = (select max( A.att_value)
from tbl_attributes A
inner join tbl_mem_att_values MAV
on MAV.att_id = A.att_id
inner join tbl_types T
on T.type_id = A.type_id
where T.type_name = 'Education'
and MAV.mem_Id = M.mem_Id),
[Profession] = (select max( A.att_value)
from tbl_attributes A
inner join tbl_mem_att_values MAV
on MAV.att_id = A.att_id
inner join tbl_types T
on T.type_id = A.type_id
where T.type_name = 'Profession'
and MAV.mem_Id = M.mem_Id)
FROM tbl_members M
The result looks like this
EM_ID MEM_EMAIL GENDER EDUCATION PROFESSION
1 it#email.com Male Graduate Engineer
2 info#email.com Female Graduate Not Working

Answer 3

Here's what you need...
SQL Fiddle
SELECT M.mem_Id,
M.mem_email,
( SELECT AA.att_value
FROM tbl_mem_att_values mv
JOIN tbl_attributes AA ON AA.att_id = mv.att_id
JOIN tbl_types TG ON TG.type_name = 'Gender' AND TG.type_id = aa.type_id
WHERE mv.mem_id = M.mem_Id) AS Gender,
( SELECT AA.att_value
FROM tbl_mem_att_values mv
JOIN tbl_attributes AA ON AA.att_id = mv.att_id
JOIN tbl_types TG ON TG.type_name = 'Education' AND TG.type_id = aa.type_id
WHERE mv.mem_id = M.mem_Id) AS Education,
( SELECT AA.att_value
FROM tbl_mem_att_values mv
JOIN tbl_attributes AA ON AA.att_id = mv.att_id
JOIN tbl_types TG ON TG.type_name = 'Profession' AND TG.type_id = aa.type_id
WHERE mv.mem_id = M.mem_Id) AS Profession
FROM tbl_members M
Brad beat me by 6 seconds

Answer 4

Just as an alternative is you want to stick to the joins:
SELECT M.mem_Id,
M.mem_email,
AA.att_value AS Gender,
AB.att_value AS Education,
AC.att_value AS Profession
FROM tbl_members M
JOIN tbl_mem_att_values mavA ON M.mem_Id = mavA.mem_id
JOIN tbl_mem_att_values mavB ON M.mem_Id = mavB.mem_id
JOIN tbl_mem_att_values mavC ON M.mem_Id = mavC.mem_id
JOIN tbl_types TA ON TA.type_name = 'Gender'
JOIN tbl_types TB ON TB.type_name = 'Education'
JOIN tbl_types TC ON TC.type_name = 'Profession'
LEFT JOIN tbl_attributes AA ON mavA.att_id = AA.att_id AND TA.type_id = AA.type_id
LEFT JOIN tbl_attributes AB ON mavB.att_id = AB.att_id AND TB.type_id = AB.type_id
LEFT JOIN tbl_attributes AC ON mavC.att_id = AC.att_id AND TC.type_id = AC.type_id
WHERE AA.type_id IN (TA.type_id, TB.type_id, TC.type_id)
AND AB.type_id IN (TA.type_id, TB.type_id, TC.type_id)
AND AC.type_id IN (TA.type_id, TB.type_id, TC.type_id)