Informatica 6, 7, 8

• Informatiemanagement
• WO
• Studiejaar 4

Informatica 6, 7, 8

6) WHERE

WHERE is used to filter data.

SELECT [Column Name]

FROM [Table Name]

WHERE [Condition];

7) Operators

• = Equal
  
• > Greater than
  
• < Less than
  
• >= Greater than or equal
  
• <= Less than or equal
  
• <>/!= Not equal. 
• BETWEEN, AND, OR, NOT

Example!

I want to select all of the data about students that are 18 or older.

SELECT * FROM StudentsTable

WHERE Age >= 18;

StudentsTable

8) ORDER BY

ORDER BY is used to sort selected data in ascending (ASC) or descending (DESC) order.

(If not specified it will be ASC by default.)

SELECT [Column Name]

FROM [Table Name]

ORDER BY [Column Name] ASC/DESC;

Example!

SELECT * 

FROM StudentsTable

ORDER BY Age DESC;

StudentsTable

SELECT _____ FROM StudentsTable

_________  _______;

Select all records from the StudentsTable, sort the result alphabetically by the column Lesson.

Lesson

ALL

ORDER BY

*

StudensTable

8) GROUP BY

The GROUP BY statement groups rows that have the same values into summary rows and often used with aggregate functions 

COUNT(), MAX(), MIN(), SUM(), AVG() to group the result-set by one or more columns.