{"id":3764,"date":"2024-04-04T20:34:19","date_gmt":"2024-04-04T13:34:19","guid":{"rendered":"https:\/\/www.sqlservertutorial.net\/?page_id=3764"},"modified":"2024-04-04T20:50:01","modified_gmt":"2024-04-04T13:50:01","slug":"sql-server-pi","status":"publish","type":"page","link":"https:\/\/www.sqlservertutorial.net\/sql-server-math-functions\/sql-server-pi\/","title":{"rendered":"SQL Server PI() Function"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the SQL Server PI()<\/code> function to obtain the constant value of Pi.<\/p>\n\n\n\n

Introduction to SQL Server PI() function #<\/a><\/h2>\n\n\n\n

In math, Pi is a constant representing the ratio of a circle’s circumference to its diameter. Pi is typically denoted by the Greek letter \u03c0<\/code> <\/p>\n\n\n\n

Pi approximately equals 3.14159<\/code>, even though its decimal representation can go on infinitely without repeating.<\/p>\n\n\n\n

In SQL Server, you can use the PI<\/code>()<\/code> function to obtain the constant value of PI<\/code>. <\/p>\n\n\n\n

Here’s the syntax of the PI()<\/code> function:<\/p>\n\n\n

PI()<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
The PI()<\/code> function returns the constant value of Pi with an accuracy of 15 digits.<\/p>\n\n\n\n
SQL Server PI() function examples #<\/a><\/h2>\n\n\n\n
Let’s take some examples of using the PI()<\/code> function.<\/p>\n\n\n\n
1) Basic PI() function example #<\/a><\/h3>\n\n\n\n
The following statement uses the PI<\/code>()<\/code> function to get the Pi<\/code> constant:<\/p>\n\n\n
SELECT<\/span> PI<\/span>() pi<\/span>;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
pi\n-----------------\n3.14159265358979<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
2) Using the PI() function to calculate the circumference of a circle #<\/a><\/h3>\n\n\n\n
The following example uses the PI()<\/code> function to calculate the circumference of a circle:<\/p>\n\n\n
DECLARE<\/span> @radius FLOAT<\/span>;\nSET<\/span> @radius = 10.0<\/span>; \n\n-- Calculating the circumference using PI() function<\/span>\nDECLARE<\/span> @circumference FLOAT<\/span>;\nSET<\/span> @circumference = 2<\/span> * PI<\/span>() * @radius;\n\n-- Display the result<\/span>\nPRINT @circumference;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
62.8319<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
How it works.<\/p>\n\n\n\n
First, declare a variable to store the radius of a circle:<\/p>\n\n\n
DECLARE<\/span> @radius FLOAT<\/span>;\nSET<\/span> @radius = 10.0<\/span>;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Second, calculate the circumference of a circle using the PI()<\/code> function:<\/p>\n\n\n
DECLARE<\/span> @circumference FLOAT<\/span>;\nSET<\/span> @circumference = 2<\/span> * PI<\/span>() * @radius;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Third, display the circumference:<\/p>\n\n\n
PRINT @circumference;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
3) Using the PI() function with table data #<\/a><\/h3>\n\n\n\n
First, create a table<\/a> called circles<\/code> that stores the radiuses of circles:<\/p>\n\n\n
CREATE<\/span> TABLE<\/span> circles(\n   id<\/span> INT<\/span> IDENTITY<\/span> PRIMARY KEY<\/span>,\n   radius DEC<\/span>(10<\/span>,2<\/span>) NOT<\/span> NULL<\/span>\n);<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
INSERT<\/span> INTO<\/span>\n  circles (radius)\nVALUES<\/span>\n  (1.5<\/span>),\n  (2.5<\/span>),\n  (3<\/span>),\n  (5<\/span>);<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Third, retrieve data from the circles<\/code> table:<\/p>\n\n\n
SELECT<\/span> * FROM<\/span> circles;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
id          radius\n----------- -------\n1<\/span>           1.50<\/span>\n2<\/span>           2.50<\/span>\n3<\/span>           3.00<\/span>\n4<\/span>           5.00<\/span>\n\n(4<\/span> rows affected)<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Finally, calculate the area of circles based on radiuses stored in the circles<\/code> table:<\/p>\n\n\n
SELECT<\/span>\n  PI<\/span>() * radius * radius area\nFROM<\/span>\n  circles;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
area\n-----------------\n7.06858347057703<\/span>\n19.6349540849362<\/span>\n28.2743338823081<\/span>\n78.5398163397448<\/span>\n\n(4<\/span> rows affected)<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
To make the areas more readable, you can use the ROUND()<\/code> function to round the area to numbers with two precisions and use the CAST<\/code> function to cast them to numbers with two decimal places:<\/p>\n\n\n
SELECT<\/span>\n  CAST<\/span>(ROUND<\/span>(PI<\/span>() * SQUARE<\/span>(radius), 2<\/span>) AS<\/span> DEC<\/span> (5<\/span>, 2<\/span>)) area\nFROM<\/span>\n  circles;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
area\n---------\n7.07<\/span>\n19.63<\/span>\n28.27<\/span>\n78.54<\/span>\n\n(4<\/span> rows affected)<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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  • Use the PI()<\/code> function to get the constant value of Pi.<\/li>\n<\/ul>\n
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Second, insert rows<\/a> into the circles<\/code> table:<\/p>\n\n\n