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SELECT MAX(SAL) FROM EMP;

SELECT MIN(SAL) FROM EMP;

SELECT AVG(SAL) FROM EMP;

SELECT SUM(SAL) FROM EMP;

SELECT COUNT(SAL) FROM EMP;

AGGREGATE FUNCTIONS (SUM, AVG, MIN, MAX, COUNT)

5000

800

2073.21

29025

14

WEEK-4B

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QUESTIONS

1-Who has the lowest salary ?

SELECT MIN(SAL) FROM EMP ; It gives the lowest salary, not owner

SELECT ENAME,MIN(SAL) FROM EMP ; NOT CORRECT

SELECT ENAME,SAL FROM EMP WHERE SAL=(SELECT MIN(SAL) FROM EMP)

2-Who has the highest salary ?

SELECT MAX(SAL) FROM EMP ; It gives the lowest salary, not owner

SELECT ENAME,MAX(SAL) FROM EMP ; NOT CORRECTSELECT ENAME,SAL FROM EMP WHERE SAL=(SELECT MAX(SAL) FROM EMP)

3-How many employees have commissions?

SELECT COUNT(COMM) FROM EMP;

4-Calculate the total salary.

SELECT SUM(SAL) FROM EMP;

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5-Calculate the average of employers salary

SELECT AVG(SAL) FROM EP;

6- List employee whose salary is greater than the average salary.

SELECT ENAME,SAL FROM EMP

WHERE SAL>(SELECT AVG(SAL) FROM EMP);

7-List employees whose salary is smaller than the average salary.

SELECT ENAME,SAL FROM EMP

WHERE SAL

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Oftentimes, we're interested in summarizing our data to determine trends or produce

top-level reports.

For example, the manager may not be interested in a listing of all widget sales, but

may simply want to know the number of widgets sold this month.Fortunately, SQL provides aggregate functions to assist with the summarization of

large volumes of data.

We'll look at functions that allow us to add and average data, count records meeting

specific criteria and find the largest and smallest values in a table.

AGGREGATE FUNCTIONS

TABLE : ORDERS

SUM AVG COUNT MIN MAX

Table ORDERS contains records of widget sales.

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SUM

It is used within a SELECT statement and, returns the summation of a series of values.

8-If you wanted to know the total number of widget sold, we could use the

following query:

SELECT SUM(QUANTITY) AS TOTAL FROM ORDERS ;

Our result would appear as :

TABLE : ORDERS

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AVG

The AVG (average) function works in a similar manner to provide the mathematical

average of a series of values. Let's try a slightly more complicated task this time.

9-We'd like to find out the average dollar amount of all orders placed on the North

American continent.

Note that we'll have to multiply the Quantity column by the UnitPrice column to compute

the dollar amount of each order.

Here's what our query will look like:

SQL> SELECT AVG(UnitPrice*Quantity) AS AveragePrice FROM ORDERS ;

And the Results :

TABLE : ORDERS

SELECT

FirstName,Quantity*UnitPrice

FROM orders ;

AVERAGE

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COUNT

SQL provides the COUNT function to retrieve the number of records in a table that meet given

criteria. We can use the COUNT(*) syntax alone to retrieve the number of rows in a table.

Alternatively, a WHERE clause can be included to restrict the counting to specific records.

10-For example, suppose You would like to know how many orders our company processed

that requested over 100 widgets.

Here's the SQL query:

SELECT COUNT(*) AS Number of Large Orders FROM Orders WHERE Quantity > 100 ;

TABLE : ORDERS

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The COUNT function also allows for the use of the DISTINCT keyword and an expression to count

the number of times a unique value for the expression appears in the target data.

Similarly, the ALL keyword returns the total number of times the expression is satisfied, without

worrying about unique values.

11-For example, You would like a simple query that returned the number of unique continents

in our orders database.

First, let's take a look at the use of the ALL keyword:

SELECT COUNT(ALL Continent) As Number of Continents FROM Orders ;

And the result set:

TABLE : ORDERS

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Obviously, this is not the desired results. If you recall the contents of the ORDERS table from

previous slide, all of our orders came from North America, Africa and Europe. Let's try the

DISTINCT keyword instead:

SQL> SELECT COUNT(DISTINCT Continent) As Number of Continents FROM Orders ;

And the output:

TABLE : ORDERS

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MAX FUNCTION

We'll look at the functionality SQL provides to locate the records containing the smallest and largest

values for a given expression.

The MAX() function returns the largest value in a given data series. We can provide the functionwith a field name to return the largest value for a given field in a table.

12-Suppose you wanted to find the order in our database that produced the most

revenue(incoming) for the company. We could use the following query to find the order with

the largest total dollar value:

SELECT MAX(Quantity * UnitPrice)As Largest Order FROM Orders ;

Our results would look like this:

select firstname,quantity*unitprice from orders ;

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MIN FUNCTION

The MINX() function returns the smallest value in a given data series. We can provide the function

with a field name to return the smallest value for a given field in a table.

13-Suppose you wanted to find the order in our database that produced the leastrevenue(incoming) for the company. We could use the following query to find the order with

the smallest total dollar value:

SELECT MIN(Quantity * UnitPrice)As Smallest Order FROM Orders ;

Our results would look like this:

SQL > SELECT FirstName,Quantity*UnitPrice FROM orders ;

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ROWNUM

ROWNUM returns a number indicating the order in which a row was selected from a table. The first

row selected has a ROWNUM of 1, the second row has a ROWNUM of 2, and so on. If a SELECT

statement includes an ORDER BY clause, ROWNUMs are assigned to the retrieved rows before

the sort is done.

You can use ROWNUM in the WHERE clause of a SELECT statement to limit the number of rows

retrieved.

SELECT A

FROM

NUMBERS

SELECT A

FROM

NUMBERS

ORDER BY A

SELECT A

FROM

NUMBERS

WHERE

ROWNUM

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CORRECT

ROWNUM=1 (ONLY FOR 1) ROWNUM BETWEEN 1 AND 5 (ONYLY STARTS WITH 1)

ROWNUM

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SELECT

NAME,SCORE

FROM ENT;

SELECT RANK()

OVER(ORDER BY SCORE DESC)

AS NO,

NAME,SCORE

FROM ENT;

SELECT DENSE_RANK()

OVER(ORDER BY SCORE DESC)

AS NO ,

NAME,SCORE

FROM ENT;

SELECT RANK()

OVER(PARTITION BY CITY ORDER BY SCORE DESC) AS NO ,

CITY,NAME,SCORE

FROM ENT;

RANK, DENSE_RANK: If you want to assign a sequential order or rank to any table, you may use RANK function.

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SELECT RANK()OVER(PARTITION BY DEPTNO ORDER BY EMPNO)

AS NO,

DEPTNO,EMPNO,ENAME,SAL

FROM EMP;

SELECT RANK()

OVER(ORDER BY EMPNO) AS NO,

DEPTNO,EMPNO,ENAME,SAL

FROM EMP;

PARTITION BY

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14-Find the most successful student (First on the ranking list by Score)

select name,score from ent

where score=(select max(score) from ent) ;

15-Find the second successful student .

SELECT * FROM

(select rank() over(order by score desc) AS NO,NAME,SCORE from ENT)WHERE NO=2 ;

ENT

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TASKS

1-Who has the lowest salary in EMP?

2-Who has the highest salary in EMP ?

3-How many employees has commission in EMP?4-How many employees have no commission in EMP?

5-Calculate the total salary in EMP.

6-Make a list with a column which ranked by line_numbers in AIRPLANES.(use Rank)

7-Make a list with a column which ranked by line_numbers in AIRPLANES.(use dense_rank)

8-Use rank function with partition to list table in AIRPLANES.

9- List the first 3 flights on customer_id='DAL' , ordered by line_number.

10-List the last flight if list is ordered by order_date.11-Make a list which ranked by city in ENT

12-Make a list which ranked by score in each city.

13-How many different departments are there in EMP table.

14-How many different jobs are there in EMP table.

15-Find the name of 8th successful student from the ENT table.

16-Find the Name of Third successful student in Almaty from ENT table;

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1)SELECT ENAME FROM EMP WHERE SAL=(SELECT MIN(SAL) FROM EMP);

2)SELECT ENAME FROM EMP WHERE SAL=(SELECT MAX(SAL) FROM EMP);

3)SELECT COUNT(*) FROM EMP wHERE COMM IS NOT NULL AND COMM!=0;

4)SELECT COUNT(*) FROM EMP wHERE COMM IS NULL OR COMM=0;

5)SELECT SUM(SAL) FROM EMP;

6)SELECT RANK() OVER(ORDER BY LINE_NUMBER) AS NO FROM AIRPLANES;

7)SELECT DENSE_RANK() OVER(ORDER BY LINE_NUMBER) AS NO FROM AIRPLANES;

8)SELECT RANK() OVER(PARTITION BY CUSTOMER_ID ORDER BY LINE_NUMBER) AS NO,CUSTOMER_ID FROM

AIRPLANES;

9)SELECT * FROM(SELECT RANK() OVER(ORDER BY LINE_NUMBER) AS NO,ORDER_DATE FROM AIRPLANES) WHEREROWNUM