May 26, 2021 Tableau
Any data analysis involves a lot of computation. /b10> In Tableau, the calculation editor is used to apply calculations to the fields being analyzed. /b11> Tableau has many built-in functions that help create complex evaluated expressions.
A description of the different categories of features is given below.
These are functions for numerical calculations. /b10> They only accept numbers as inputs. H ere are some examples of important numeric functions.
| Function | Describe | Example |
|---|---|---|
| CEILING(number) | Round the number to the nearest integer equal to or greater than the value. | CEILING(2.145)= 3 |
|
POWER (number, power)
|
Power the numbers. | POWER(5,3)= 125 |
|
ROUND (number, [decimals])
|
Round the numbers to the specified number of digits. | ROUND(3.14152,2)= 3.14 |
String functions are used for string operations. /b10> Here are some important string functions and examples.
| Example | Describe | Example |
|---|---|---|
| LEN(string) | Returns the length of the string. | LEN(“Tableau")= 7 |
| LTRIM(string) | Returns a string that deleted any leading spaces. | LTRIM(“Tableau")=“Tableau" |
| REPLACE(string，substring，replacement) | Search for strings to get substrings and replace them with replacements. /b10> If no substring is found, the string is not changed. | REPLACE(“GreenBlueGreen"，“Blue"，“Red")=“GreenRedGreen" |
| UPPER(string) | Returns a string, all characters are capital. | UPPER(“Tableau")=“TABLEAU" |
Tableau has a variety of date functions to perform calculations involving dates. /b10> All date functions use date_part, which is a string that represents part of a date, such as - month, day, or year. /b11> Here are some examples of important date functions.
| Example | Describe | Example |
|---|---|---|
| DATEADD(date_part，increment，date) | Returns the increment added to the date. /b10> The type of increment date_part in the file. | DATEADD(\'month\'，3，＃2004-04-15＃)= 2004-07-15 12:00:00 AM |
| DATENAME (date_part, date, start_of_week) | The date on which the date of the date of the date is passed back as a string. /b10> start_of_week parameters are optional. | DATENAME ('month', #2004-04-15) |
| DAY(date) | Returns the date of a given date as an integer. | DAY(＃2004-04-12＃)= 12 |
| NOW() | Returns the current date and time. | NOW()= 2004-04-15 1:08:21 PM |
These functions evaluate a single value or result of an expression and give a Boolean output.
| Example | Describe | Example |
|---|---|---|
| IFNULL(expression1，expression2) | If the result is not null, the IFNULL function returns the first expression, and if the result is empty, the second expression is returned. | IFNULL([Sales]，0)= [Sales] |
| ISDATE(string) | If string parameters can be converted to dates, the ISDATE function returns TRUE, and if they cannot be converted to dates, FALSE. |
ISDATE(“11/05/98")= TRUE
ISDATE(“14/05/98")= FALSE |
| MIN(expression) | The MIN function returns the minimum value of all recorded expressions or a minimum of two expressions per record. | |
| Example | Describe | Example |
|---|---|---|
| AVG(expression) | Returns the average of all values in the expression. /b10> AVG can only be used with numeric fields. /b11> The empty value is ignored. | |
| COUNT(expression) | Returns the number of items in the group. /b10> Empty values are not calculated. | |
| MEDIAN(expression) | Returns the median expression for all records. /b10> The median can only be used with numeric fields. /b11> The empty value is ignored. | |
| STDEV(expression) | Returns a statistical standard deviation for all values in a given expression based on the sample population. |