SQL Functions
SQL has many built-in functions for performing calculations on data.
SQL Aggregate Functions
SQL aggregate functions return a single value, calculated from values in a column.
Useful aggregate functions:
- AVG() - Returns the average value
- COUNT() - Returns the number of rows
- FIRST() - Returns the first value
- LAST() - Returns the last value
- MAX() - Returns the largest value
- MIN() - Returns the smallest value
- SUM() - Returns the sum
SQL Scalar functions
SQL scalar functions return a single value, based on the input value.
Useful scalar functions:
- UCASE() - Converts a field to upper case
- LCASE() - Converts a field to lower case
- MID() - Extract characters from a text field
- LEN() - Returns the length of a text field
- ROUND() - Rounds a numeric field to the number of
decimals specified
- NOW() - Returns the current system date and time
- FORMAT() - Formats how a field is to be displayed
Tip: The aggregate functions and the scalar functions will be explained in details in the next chapters.
Click here to design a Stunning Flash Website for Free
Wix is a revolutionary web design tool that provides anyone with the possibility to create professional and beautiful websites for free.
With e-commerce features, search engine visibility and many more professional tools, Wix is the ultimate solution for creating a spectacular site while saving tons of money.
 |
W3Schools' Online Certification Program
The perfect solution for professionals who need to balance work, family, and career building.
More than 4000 certificates already issued!
|
The HTML Certificate documents your knowledge of HTML, XHTML, and CSS.
The JavaScript Certificate documents your knowledge of JavaScript and HTML DOM.
The XML Certificate documents your knowledge of XML, XML DOM and XSLT.
The ASP Certificate documents your knowledge of ASP, SQL, and ADO.
The PHP Certificate documents your knowledge of PHP and SQL (MySQL).
| 
