Need some help with query

[alvinguy]

Hi Guys,

I'm working on a SQL problem and am a bit stuck. I'll have to apologize for I'm still very new to this and can't do a lot of complex queries yet. I've attached what I've done so far, thank you in advance for your help.

Given the following relation schemas:

EMPLOYEE(SSN, NAME, SEX, DNUMBER)
DEPARTMENT(DNUMBER, DNAME, DMGRSSN)
DLOCATION(DNUMBER, DLOCATION)
PROJECT(PNUMBER, PNAME, PLOCATION)
WORKSON(SSN, PNUMBER, HOURS)

Write the following queries in SQL:

1. List the name(s) of employee(s) who works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER = b. PNUMBER and b.PLOCATION= ‘Houston’

2. List the name(s) of employee(s) who only works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER=b.PNUMBER and b.PLOCATION in (‘Houston’) and ???

3. List the name(s) of employee(s) who works(work) on every project except the one(s) located in Houston.

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c. PNUMBER=b.PNUMBER and b.PLOCATION not in (‘Houston’)

4. List name(s) of employee(s) who works(work) on exactly all projects located in ‘Houston.’

???

[Vidhura]

Hi Guys,

I'm working on a SQL problem and am a bit stuck. I'll have to apologize for I'm still very new to this and can't do a lot of complex queries yet. I've attached what I've done so far, thank you in advance for your help.

Given the following relation schemas:

EMPLOYEE(SSN, NAME, SEX, DNUMBER)
DEPARTMENT(DNUMBER, DNAME, DMGRSSN)
DLOCATION(DNUMBER, DLOCATION)
PROJECT(PNUMBER, PNAME, PLOCATION)
WORKSON(SSN, PNUMBER, HOURS)

Write the following queries in SQL:

1. List the name(s) of employee(s) who works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER = b. PNUMBER and b.PLOCATION= ‘Houston’

2. List the name(s) of employee(s) who only works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER=b.PNUMBER and b.PLOCATION in (‘Houston’) and ???

3. List the name(s) of employee(s) who works(work) on every project except the one(s) located in Houston.

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c. PNUMBER=b.PNUMBER and b.PLOCATION not in (‘Houston’)

4. List name(s) of employee(s) who works(work) on exactly all projects located in ‘Houston.’

???

Try to use joins instead of alias names
sample:
3. List the name(s) of employee(s) who works(work) on every project except the one(s) located in Houston.

SELECT a.NAME from Project b
left join WORKSON c on C.Pnumber=b.Pnumber
left join EMPLOYEE a on a.SSN=c.SSN
WHERE b.PLOCATION !=‘Houston’

2. List the name(s) of employee(s) who only works(work) on every project located in ‘Houston.’

select distinct Employee.Name from Project
left join Workson on Workson.PNumber=Project.PNumber
left join Employee on Employee.SSN=Workson.SSN
where Project.PLOcation='Houston'

4. List name(s) of employee(s) who works(work) on exactly all projects located in ‘Houston.’

Select Name from Employee where SSN=(Select SSN from
(Select SSN,count(SSN) as cnt from
(select distinct SSN,Workson.PNumber from Project
left join Workson on Workson.Pnumber= Project.PNumber
where Project.PLocation='Houston'
group by SSN,Workson.PNumber) as A
group by SSN) as B
where cnt=(select Count(Pnumber) from Project Where Plocation='Houston'))

[mandy1]

Hi Guys,

I'm working on a SQL problem and am a bit stuck. I'll have to apologize for I'm still very new to this and can't do a lot of complex queries yet. I've attached what I've done so far, thank you in advance for your help.

Given the following relation schemas:

EMPLOYEE(SSN, NAME, SEX, DNUMBER)
DEPARTMENT(DNUMBER, DNAME, DMGRSSN)
DLOCATION(DNUMBER, DLOCATION)
PROJECT(PNUMBER, PNAME, PLOCATION)
WORKSON(SSN, PNUMBER, HOURS)

Write the following queries in SQL:

1. List the name(s) of employee(s) who works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER = b. PNUMBER and b.PLOCATION= ‘Houston’

2. List the name(s) of employee(s) who only works(work) on every project located in ‘Houston.’

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c.PNUMBER=b.PNUMBER and b.PLOCATION in (‘Houston’) and ???

3. List the name(s) of employee(s) who works(work) on every project except the one(s) located in Houston.

SELECT a.NAME
FROM EMPLOYEE a, PROJECT b, WORKSON c
WHERE a.SSN = c.SSN and c. PNUMBER=b.PNUMBER and b.PLOCATION not in (‘Houston’)

4. List name(s) of employee(s) who works(work) on exactly all projects located in ‘Houston.’

???

Hi
Different way for different queries exist.
if u still have problem in 3rd query u can use the following.

SELECT a.NAME
FROM
EMPLOYEE AS a, WORKSON AS b
WHERE a.SSN=b.SSN and b.PNUMBER IN
(SELECT PNUMBER
FROM PROJECT
WHERE PLOCATION NOT IN('HOUSTON'));

IF U STILL HAVE ANY PROBLEM IN ANY OTHER QUERY PLZ TELL I WILL TRY MY BEST TO SOLVE THAT ONE.