MySQL VAR_SAMP() function
VAR_SAMP() function
MySQL VAR_SAMP() function returns the sample variance of a given expression. Variance is a measure of how spread out or dispersed a set of data points is.
This function is useful in -
- Variance is a key parameter in statistics that provides insights into the dispersion of data points around the mean.
- Variance can indicate how much your data points vary from the average. High variance might suggest inconsistencies or outliers in the data.
- In fields like finance, understanding the variance of returns on investments helps in assessing risk. A higher variance might indicate higher risk.
- In manufacturing or process control, variance can be used to monitor the consistency and quality of products.
- When dealing with scientific experiments or surveys, analyzing the variance of measurements can provide insights into the reliability of the results.
Syntax
VAR_SAMP(expr);
Where expr is an expression.
MySQL Version: 8.0
Example:
Sample table: purchase
Code:
SELECT VAR_SAMP(total_cost)
FROM purchase;
Explanation
The following statement returns the sample variance of 'total_cost' from purchase table.
Output:
mysql> SELECT VAR_SAMP(total_cost) -> FROM purchase; +----------------------+ | VAR_SAMP(total_cost) | +----------------------+ | 119366.666667 | +----------------------+ 1 row in set (0.00 sec)
Example: MySQL VAR_SAMP() with where clause
The following statement returns the sample variance of 'expr' 'total_cost' from purchase table for the category 'cate_id' as given with WHERE clause.
Sample table: purchase
Code:
SELECT VAR_SAMP(total_cost)
FROM purchase
WHERE cate_id='CA001';
Output:
mysql> SELECT VAR_SAMP(total_cost) -> FROM purchase -> WHERE cate_id='CA001'; +----------------------+ | VAR_SAMP(total_cost) | +----------------------+ | 236875.000000 | +----------------------+ 1 row in set (0.00 sec)
Previous:
VAR_POP()
Next:
VARIANCE()
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