Data Manipulation 2 1

After this lecture, you should be able to: Use SQL SELECT statement effectively to

retrieve the data from multiple related tables. Join Operation Aliasing of Tables

Brainstorm on Assignment 3 (Part 1).

Data Manipulation 2

Data Manipulation 2 2

Review: Get the S#'s, cities, and statuses of the suppliers in Athens or Paris. Sort the resultant table in the descending order of statuses.

sno | city | status----------------------- s3 | Paris | 30 s5 | Athens | 30 s2 | Paris | 10

select sno, city, status from s where city in (‘Athens’, ‘Paris’) order by status desc;

Table S sno | sname | status | city----------------------------- s1 | Smith | 20 | London s2 | Jones | 10 | Paris s3 | Blake | 30 | Paris s4 | Clark | 20 | London s5 | Adams | 30 | Athens

Data Manipulation 2 3

Select Statements

Select columns – Projection From – Database tables Where -- Selection condition Group By – Partitioning data into

groups Having -- Group selection condition Order By -- Sorting

Select [Distinct] column(s)From table(s)Where condition[ Group By field(s) ][ Having condition ][ Order By field(s) ] ;

Data Manipulation 2 4

Get the names and cities of the suppliers who supplied P4.

Table S Table SP sno | sname | status | city sno | pno | qty ----------------------------- --------------- s1 | Smith | 20 | London s1 | p1 | 300 s2 | Jones | 10 | Paris s1 | p4 | 200 s3 | Blake | 30 | Paris s2 | p3 | 400 s3 | p4 | 100

select sname, cityfrom s, spwhere s.sno = sp.sno and sp.pno = ‘p4’;

sname city ----- ------ Smith London Blake Paris

Join Operation

Data Manipulation 2 5

Who supplied blue parts?

Table S Table Psno | sname | sts | city pno | pname | color | wgt | city-------------------------- ---------------------------------- s1 | Smith | 20 | London p1 | nut | red | 12 | London s2 | Jones | 10 | Paris p2 | bolt | green | 17 | Paris p3 | screw | blue | 17 | Rome

Table SP sno | pno | qty --------------- s1 | p1 | 300 s2 | p3 | 200

select snamefrom s, sp, pwhere s.sno = sp.sno and sp.pno = p.pno and color = 'blue' ;

sname-------- Jones

Data Manipulation 2 6

List the names and the colors of the parts supplied by the suppliers located in London.

select pname, colorfrom s, p, spwhere s.sno = sp.sno and sp.pno = p.pno and s.city = ‘London’ ;

pname | color -------------- nut | red bolt | green

Table S Table Psno | sname | sts | city pno | pname | color | wgt | city-------------------------- ---------------------------------- s1 | Smith | 20 | London p1 | nut | red | 12 | London s2 | Jones | 10 | Paris p2 | bolt | green | 17 | Rome p3 | screw | blue | 17 | Rome Table SPsno | pno | qty---------------s1 | p1 | 300s1 | p2 | 250s2 | p3 | 200

Data Manipulation 2 7

Aliasing of Tables

Which parts are of the same color?

select px.pno, py.pno, px.colorfrom p px, p pywhere px.color = py.color and px.pno < py.pno ;

px.pno | py.pno | color ----------------------- p2 | p3 | blue p1 | p4 | red

Table P pno | pname | color -------------------- p1 | nut | red p2 | screw | blue p3 | cam | blue p4 | cog | red

Table P PX Table P PYpno | pname | color pno | pname | color-------------------- -------------------- p1 | nut | red p1 | nut | red p2 | screw | blue p2 | screw | blue p3 | cam | blue p3 | cam | blue p4 | cog | red p4 | cog | red

Data Manipulation 2 8

Get the (distinct) names of the cities where both blue and green parts are located?

select distinct px.cityfrom p px, p pywhere px.color = ‘blue’ and py.color = ‘green’ and px.city = py.city;

City-------- London Rome

Table P pno | pname | color | wgt | city ---------------------------------- p1 | nut | blue | 12 | London p2 | bolt | green | 17 | Rome p3 | screw | blue | 15 | Rome p4 | cog | green | 18 | London p5 | cam | red | 19 | Athens

Data Manipulation 2 9

Get the names of the suppliers who supplied p1 and p2.

Table S Table SP sno | sname | status | city sno | pno | qty ----------------------------- --------------- s1 | Smith | 20 | London s1 | p1 | 300 s2 | Jones | 10 | Paris s1 | p3 | 200 s3 | Blake | 30 | Paris s2 | p1 | 400 s2 | p2 | 100 s2 | p3 | 50 s3 | p2 | 80

select snamefrom s, sp spx, sp spywhere s.sno = spx.sno and spx.pno = ‘p1’ and s.sno = spy.sno and spy.pno = ‘p2’;

sname ----- Jones