1. STRUCTURED QUERY LANGUAGE (SQL)
Chapter 5:
Part 2:
DML
STRUCTURED QUERY LANGUAGE (SQL)

2. Objectives To be able to apply SQL command. How to use DML in SQL
2 major components:
Data Definition Language (DDL)
defining database structure.
allows database objects such as schemas, domains, tables, views and indexes to be created and destroyed.
Data Manipulation Language (DML)
retrieving and updating data.
used to populate and query the tables.
data manipulation.

3. DML
Data Manipulation Language
Manipulate data

4. Data Manipulation Language(DML)
Data Manipulation in SQL is an ability for
manipulating the data to provide information needs by users.
Manipulating the data referees to process of:
selecting the data
do some operation at the data
user view it or save it in the database
SELECT *
FROM printer
WHERE color = ‘red’ OR color = ‘blue’;

5. DML: Queries: SELECT Statement
The SELECT statement allows you to find, retrieve, and display data.
To execute the SELECT statement on a table, you must be the table owner, have DBA or SYSADM security privileges, or have the SELECT privilege for that table.
The result of SELECT statement is a set of rows known as the result set, which meets the conditions specified in the SELECT statement
SQL SELECT Syntax
Note
SQL is not case sensitive { SELECT is the same as select }
SELECT column_name(s)
FROM table_name;
SELECT *
FROM table_name;

6. DML: Queries: SELECT Statement
Select all data from table printer.
Select printerNO and price from table printer.
SELECT *
FROM printer;
printerNO
description
color
price
P123
Dot-matrix
Red
249.56
HP874
Laser Jet
Blue
559.99
SELECT printerNO, price
FROM printer;
printerNO
price
P123
249.56
HP874
559.99

7. DML: Queries: SELECT DISTINCT Statement
In a table, some of the columns may contain duplicate values.
The DISTINCT keyword can be used to return only distinct (different) values.
SQL SELECT DISTINCT Syntax
SELECT DISTINCT column_name(s)
FROM table_name;

8. DML: Queries: SELECT DISTINCT Statement
The following statement only will select the distinct values from the column named city from table staff.
staffNO
staffNAME
city
ABC987
Nadz
Kuala Lumpur
ABC988
Aina
Jerantut
ABC999
Halimaton
SELECT DISTINCT city
FROM staff;
city
Kuala Lumpur
Jerantut

9. SQL LIKE Operator
The LIKE operator is used in a WHERE statement to search for a specified pattern in a column.
SQL LIKE Syntax
Note
The LIKE operator is commonly used with SQL Wildcards
SELECT column_name(s)
FROM table_name
WHERE column_name LIKE patern;

10. SQL LIKE Operator
The following select staffs living in a city start with “K” from table ‘staff’.
SELECT *
FROM staff
WHERE city LIKE “K%”;
staffNO
staffNAME
city
ABC987
Nadz
Kuala Lumpur

11. SQL Wildcards % _ [charlist] [^charlist] or [!charlist]
SQL wildcards can be used when searching for data in a database.
SQL wildcards can substitute for one or more characters when searching for data in a database.
SQL wildcards must be used with the SQL LIKE operator.
With SQL, the following wildcards can be used:
Wildcard
Description %
A substitute for zero or more characters _
A substitute for exactly one character
[charlist]
Any single character in charlist
[^charlist] or
[!charlist]
Any single character not in charlist

12. Wildcards: Using The % Wildcard
Select staff living in the city that start with ‘La’ from staff table. Select staff living in the city that contain pattern ‘wi’ from staff table.
SELECT *
FROM staff
WHERE city LIKE "La%";
SELECT *
FROM staff
WHERE city LIKE "%wi%";

13. Wildcards: Using The _ Wildcard
Select staff with a name that starts with any character, followed by ‘da’ from staff table. Select staff with a name that starts with "S", followed by any character, followed by "ar", followed by any character, followed by "s" from staff table.
SELECT *
FROM staff
WHERE staffNAME LIKE "_da";
SELECT *
FROM staff
WHERE staffNAME LIKE "S_ar_s";

14. Wildcards: Using The [charlist] Wildcard
Select staff with a name that starts with "a" or "s" or "p" from staff table. Select staff name that do not starts with “"a" or "s" or "p" from staff table.
SELECT *
FROM staff
WHERE staffNAME LIKE "[asp]%";
SELECT *
FROM staff
WHERE staffNAME LIKE "[!asp]%";

15. DML: Data Entry The INSERT INTO command inserts new rows into a table.
When you insert data into a child table that has a foreign key linking it to a parent table, you must obey referential integrity rules.
This means you cannot insert a value into a child key that does not exist in the parent key unless it is a NULL value.
You must insert a new row into the parent key first.
To insert a string that contains a single quote, you must replace the single quote in the string with two consecutive single quotes.

16. DML: Data Entry SQL INSERT INTO Syntax
It is possible to write the INSERT INTO statement in two forms.
The first form doesn't specify the column names where the data will be inserted, only their values:
The second form specifies both the column names and the values to be inserted:
INSERT INTO table_name
VALUES (value1, value2,…);
INSERT INTO table_name (column1,column2,…)
VALUES (value1, value2,…);

17. DML: Data Entry The following insert values into table ‘staff’.
INSERT INTO staff
VALUES (‘ABC123’, ‘Norain', ‘Ipoh’);
staffNO
staffNAME
city
ABC123
Norain
Ipoh

18. DML: Data Entry Insert a new customer for the following table.
insert into tblcustomer (customerno, customername, customer )
values (‘C001’, ‘Alya Qiesya’,

19. DML: Deleting Table Rows
The DELETE command deletes all rows matching the search condition from a table.
You can only delete rows from a single table, and you cannot delete rows from the system tables.
To execute the DELETE command, you must be the table owner, have delete privilege on the table, or have DBA or SYSADM security privileges.

20. DML: Deleting Table Rows
SQL DELETE Syntax
Note
Notice the WHERE clause in the DELETE syntax. The WHERE clause
specifies which record or records that should be deleted. If you omit the
WHERE clause, all records will be deleted!
DELETE FROM table_name
WHERE some column=some value

21. DML: Deleting Table Rows
DELETE record as specified in WHERE clause.
The following example deletes all staff whose name begins with “Muhammad" from the staff table.
The following example deletes staff number ABC125 from the staff table.
DELETE FROM staff
WHERE staffNO=“ABC123” AND city=“Ipoh”;
DELETE FROM staff
WHERE staffNAME LIKE “Muhammad%”;
DELETE FROM staff
WHERE staffNO =“ABC125”;

22. DML: Making Changes to Data Items
The UPDATE command updates existing rows in a table.
When you update a column, the new column values must satisfy the column constraints and referential integrity.
If the column has a DEFAULT value defined, you can use the DEFAULT keyword to set the value of the column to the default value.

23. DML: Making Changes to Data Items
SQL UPDATE Syntax
Note
Notice the WHERE clause in the UPDATE syntax. The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!
UPDATE table_name
SET column1=value,column2=value2,…
WHERE some column=some value

24. DML: Making Changes to Data Items
Shows how to update the staff table and change the city value for staff named “Rosliza".
Shows how to give a salary raise of 5% to staff named “Wafiy".
Update description for printer with printerNO F380.
UPDATE staff
SET city=“Bangi”
WHERE staffNAME = “Rosliza”;
UPDATE staff
SET salary=salary*1.05
WHERE staffNAME = “Wafiy”;
UPDATE printer
SET description=“KO”
WHERE printerNO = “F380”;

25. DML: COMMIT
The COMMIT statement terminates the current transaction and makes all
changes under the transaction persistent.
COMMIT  is used for saving the data that has been changed permanently because whenever you perform any DML like UPDATE, INSERT or DELETE then you are required to write COMMIT at the end of all or every DML operation in order to save it permanently.
If you do not write COMMIT and your program crashes then your data will be restored into its previous condition.
The COMMIT statement has the following general format:
UPDATE printer SET indate = ‘15/01/2007'
WHERE printerNO = 'F380';
COMMIT;

26. DML: ROLLBACK
The ROLLBACK statement terminates the current transaction and cancel all changes made under the transaction.
ROLLBACK is used if you want to restore your data into its previous condition.
ROLLBACK can be write at any time after the DML queries has been written but remember once COMMIT has been written then you cannot rollback the data.
You can only rollback the DML queries that have been written after the last commit statement.
The ROLLBACK statement has the following general format:
INSERT INTO staff
VALUES (“ABC990”, “Shafiza”, “Johor”)
ROLLBACK;

27. DML: COMMIT & ROLLBACK
The concept of COMMIT and ROLLBACK is designed for  data consistency
because many uses manipulate data of the same table, using the same
database so the user must get updated data.  That is why COMMIT and
ROLLBACK are used for.
COMMIT
to save whatever has been done. It is used to permanently store it in memory.
ROLLBACK
to undo something. If we use roll-back, the particular changes made are undone.

28. DML: Compound Statement with SELECT
You can combine simple conditions with the logical operators
AND, OR, and NOT to form compound conditions.
Symbol
Meaning =
Equal to
<
Less than
<=
Less than or equal to
>
Greater than
>=
Greater than or equal to
<>
Not equal to*
*Some SQL version use !=
AND
to combine two search conditions which must be both true. OR
to combine two search conditions when one or the other (or both) must be true

29. DML: Compound Statement with SELECT
Select only the staff live in Jengka AND age greater then or equal to 40 years old from table staff. Select only the staff live in Temerloh OR age greater then or equal to 40 years old from table staff.
SELECT *
FROM staff
WHERE city=“Jengka” AND age >= 40;
SELECT *
FROM staff
WHERE city=“Temerloh” AND age >= 40;

30. DML: Compound Statement with SELECT
Select only the staff live in Jengka OR Temerloh AND age greater then or equal to 40 years old from table staff.
SELECT *
FROM staff
WHERE (city=“Jengka” OR city=“Temerloh”) AND age >= 40;

31. Do it! Delete all biscuits with chocolate flavor from tblbiscuit.
Delete all order from customerC001 that have status cancel from tblorder.
tblcustomer(custNO, custNAME, cust )
tblbiscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
tblorder(orderNO,*custNO,*bisNO, orderadate, qty, status)
delete from tblbiscuit
where bisFLAVOUR = “chocolate”;
delete from tblorder
where custNO = “C001” and status = “cancel”;

32. Change all status to confirm for biscuit BIS101 for customer C135.
Increase biscuit price 10% for biscuit with strawberry flavor.
tblcustomer(custNO, custNAME, cust )
tblbiscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
tblorder(orderNO,*custNO,*bisNO, orderadate, qty, status)
update tblorder
set status = “confirm”
where custNO = “C135”;
update tblbiscuit
set bisPRICE=bisPRICE*1.01
where bisFLAVOUR = “strawberry”;

33. List down all customer name and email who order biscuit cornflakes.
List down all biscuit details being order by customer C010.
tblcustomer(custNO, custNAME, cust )
tblbiscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
tblorder(orderNO,*custNO,*bisNO, orderadate, qty, status)
select c.custNAME, c.cust
from tblcustomer c, tblorder o, tblbiscuit b
where c.custNO=o.custNo and o.bisNO=b.bisNo and b.bisNAME = “cornflakes”;
select b.bisNO, b.bisNAME, b.bisFLAVOUR, b.bisPRICE
from tblbiscuit b, tblorder o
where b.bisNO=o.bisNO and o.custNO=“C010”;

34. SQL Alias
You can give a table or a column another name by using an alias. This can be a good thing to do if you have very long or complex table names or column names.
An alias name could be anything, but usually it is short.
Usually it is used in multiple table joint.
SQL Alias Syntax For Tables
SQL Alias Syntax For Columns
SELECT column_name(s)
FROM table_name
AS alias_name
SELECT column_name AS alias_name
FROM table_name

35. SQL Alias staff department
staffNO
staffNAME
city
salary
departNO
ABC987
Nadz
Kuala Lumpur
2300
0001
ABC988
Aina
Jerantut
2500
0002
ABC989
Halimaton
2200
ABC990
Norain
Johor
2000
0003
departNO
departNAME
0001 IT
0002
Network
0003
Management
The following statement list all the staff name that work at IT department.
SELECT s.staffNAME
FROM staff AS s, department AS d
WHERE (d.departNO=s.departNO) AND d.departNAME=“IT”;
staffNAME
Nadz
Halimaton

36. SQL JOINs
The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.
Tables in a database are often related to each other with keys.
A primary key is a column (or a combination of columns) with a unique value for each row. Each primary key value must be unique within the table. The purpose is to bind data together, across tables, without repeating all of the data in every table.

37. SQL JOINs Different SQL JOINs JOIN / INNER JOIN
Return rows when there is at least one match in both tables
LEFT JOIN
Return all rows from the left table, even if there are no matches in the right table
RIGHT JOIN
Return all rows from the right table, even if there are no matches in the left table
FULL JOIN
Return rows when there is a match in one of the tables

38. SQL INNER JOIN SQL INNER JOIN Syntax SELECT column_name(s)
NOTE
INNER JOIN is the same as JOIN.
SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name = table_name2.column_name

39. SQL INNER JOIN staff department
staffNO
staffNAME
city
salary
departNO
ABC987
Nadz
Kuala Lumpur
2300
0001
ABC988
Aina
Jerantut
2500
0002
ABC989
Halimaton
2200
ABC990
Norain
Johor
2000
0003
departNO
departNAME
0001 IT
0002
Network
0003
Management
The following statement list all the staff name that work at IT department.
SELECT staff.staffNAME,depart.departNAME
FROM staff
INNER JOIN department
ON department.departNO=staff.departNO;
staffNAME
Nadz
Halimaton

40. DML: Two-Table Joins SELECT s.staffNAME
Besides INNER JOIN, you can also use the following statements to combines two tables with join conditions.
staff(staffNO, staffNAME, city, salary, departmentNO*)
department(departNO, departNAME)
SELECT s.staffNAME
FROM staff AS s, department AS d
WHERE (d.departNO=s.departNO) AND d.departNAME=“IT”;
SELECT staff.staffNAME,department.departNAME
FROM staff
INNER JOIN department
ON department.departNO=staff.departNO;

41. DML: Multiple-Table Joins
A multiple table join is a join of more than two tables with join conditions for pairs of table.
A join condition is a comparison (relational operators) on two columns from each table.
Following is a three table joins which selects all the customer name that order biscuit Tart Nenas Gunting.
customer(custNO, custNAME, cust )
biscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
order(orderNO,*custNO,*bisNO, orderadate, qty, status)
SELECT custNAME
FROM customer AS c, biscuit AS b, order AS o
WHERE c.custNO=o.custNO AND o.bisNO=b.bisNO
AND b.bisNAME=“Tart Nenas Gunting“;

42. DML: Multiple-Table Joins
List down all customer name, biscuit name and order quantity that customer had order with confirm status.
tblcustomer(custNO, custNAME, cust )
tblbiscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
tblorder(orderNO,*custNO,*bisNO, orderadate, qty, status)
select c.custNAME,b.bisNAME,o.qty
from tblcustomer c, tblbiscuit b, tblorder o
where c.custNO=o.custNO and b.bisNO=o.bisNO and o.status=“Confirm”;

43. DML: GROUP BY Statement
produce summary data within a group.
a group is a set of rows that have the same values of group by columns.
a single row of aggregate results is produced for each group.
the column you want to group results by is identified by its column name.
restrict what you can enter in the SELECT statement.
SELECT statement in GROUP BY statement must be one of the following:
An aggregate function, which produces a single value summarizing the rows in the group.
A grouping column which is listed in the GROUP BY statement.
A constant.
An expression involving a combination of the above.

44. DML: GROUP BY Statement
SQL GROUP BY Syntax
SELECT column_name(s), aggregate_function(column_name)
FROM table_name
GROUP BY column_name;

45. DML: GROUP BY Statement
staff
staffNO
staffNAME
city
salary
gender
departNO
ABC987
Nadz
Kuala Lumpur
2300
Male
0001
ABC988
Aina
Jerantut
2500
Female
0002
ABC989
Halimaton
2200
ABC990
Norain
Johor
2000
0003
The following statement will output staff average salary group by city.
SELECT city, MIN(salary) AS minSALARY
FROM staff
GROUP BY city;
city
minSALARY
Kuala Lumpur
2300
Jerantut
2200
Johor
2000

46. DML: ORDER BY Keyword The ORDER BY keyword
is used to sort the result-set by a specified column.
sort the records in ascending order by default.
By default the records are in ascending order or you can used ASC keyword
If you want to sort the records in a descending order, you can use DESC keyword.
The default order is ascending. NULL values are treated as larger that non- null values for sorting purposes.
SQL ORDER BY Syntax
SELECT column_name(s)
FROM table_name
ORDER BY column_name(s) ASC|DESC

47. DML: ORDER BY Keyword staff
staffNO
staffNAME
city
salary
gender
departNO
ABC987
Nadz
Kuala Lumpur
2300
Male
0001
ABC988
Aina
Jerantut
2500
Female
0002
ABC989
Halimaton
2200
ABC990
Norain
Johor
2000
0003
The following statement will output staff average salary group by city.
SELECT city, MIN(salary) AS minSALARY
FROM staff
GROUP BY city
ORDER BY city DESC;
city
minSALARY
Jerantut
2200
Johor
2000
Kuala Lumpur
2300

48. DML: HAVING Statement
HAVING statement is used to select or reject a group.
The following example shows the average salary for staff based on city where the total staff salary exceeds RM 2000.
staffNO
staffNAME
city
salary
gender
departNO
ABC987
Nadz
Kuala Lumpur
2300
Male
0001
ABC988
Aina
Jerantut
2500
Female
0002
ABC989
Halimaton
2200
ABC990
Norain
Johor
2000
0003
SELECT city, AVG(salary) AS avgSALARY
FROM staff
GROUP BY city
HAVING SUM(salary)> 2000 ;
city
avgSALARY
Kuala Lumpur
2300
Jerantut
2350

49. SQL Aggregate Functions
SQL aggregate functions return a single value, calculated from values in a column
COUNT( ) returns the number of rows
SUM( ) returns the sum
AVG( ) returns the average value
MIN( ) returns the smallest value
MAX( ) returns the largest value
FIRST( ) returns the first value
LAST( ) returns the last value

50. SQL Aggregate Functions
Each operates on a single column of a table and returns a single value.
COUNT, MIN, and MAX apply to numeric and non-numeric fields
SUM and AVG may be used on numeric fields only.
Apart from COUNT(*), each function eliminates nulls first and operates only on remaining non-null values.
COUNT(*) counts all rows of a table, regardless of whether nulls or duplicate values occur.
Can use DISTINCT before column name to eliminate duplicates.
DISTINCT has no effect with MIN/MAX, but may have with SUM/AVG.

51. MIN/MAX/AVG
pen
penNO
descr
color
qty
1001
Xtra-Fine
Red 12
1002
Fine
Blue 32
1003
Medium
Pink 4
SELECT MIN(qty)AS minQTY, MAX(qty) AS maxQTY, AVG(qty) AS avgQTY
FROM pen;
minQTY
maxQTY
avgQTY 4 32 16

52. SUM/COUNT pen SELECT SUM(qty)AS totalQTY FROM pen;
penNO
descr
color
qty
1001
Xtra-Fine
Red 12
1002
Fine
Blue 32
1003
Medium
Pink 4
SELECT SUM(qty)AS totalQTY
FROM pen;
totalQTY 48
SELECT COUNT(penNO)AS penNUMBER
FROM pen;
penNUMBER 3

53. FIRST/LAST pen SELECT FIRST(color)AS firstCOLOR FROM pen;
penNO
descr
color
qty
1001
Xtra-Fine
Red 12
1002
Fine
Blue 32
1003
Medium
Pink 4
SELECT FIRST(color)AS firstCOLOR
FROM pen;
firstCOLOR
Red
SELECT LAST(color)AS lastCOLOR
FROM pen;
lastCOLOR
Pink

54. Find biscuit name that have the highest price.
List down all the biscuit order quantity for each biscuit type.
List down all the biscuit order quantity for each customer and sort according to the customer name.
List down how many customer order being made for each biscuit.
List down all customer name and who order more then 5 biscuits.
List down biscuit information that never being order yet.
tblcustomer(custNO, custNAME, cust )
tblbiscuit(bisNO, bisNAME, bisFLAVOUR, bisPRICE)
tblorder(orderNO,*custNO,*bisNO, orderadate, qty, status)

55. Find biscuit name that have the highest price.
SELECT bisNAME
FROM tblbiscuit
WHERE bisPRICE = (SELECT MAX(bisPRICE) FROM tblbiscuit);