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.’
???