MySQL ANY_VALUE() Function Explained

In MySQL, ANY_VALUE() is an aggregate function that allows us to include nonaggregated columns in the SELECT list when using the GROUP BY clause.

The ANY_VALUE() function is commonly used to resolve issues that arise when a query includes columns that are not part of the GROUP BY clause or aggregate functions. It can be useful in scenarios where we want to include descriptive columns in a grouped result set without affecting the grouping behaviour.

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Understanding the VAR_SAMP() Function in MySQL

In MySQL, the VAR_SAMP() function returns the sample variance of an expression. The denominator is the number of rows minus one.

If there are no matching rows, or if the expression is NULLVAR_SAMP() returns NULL.

VAR_SAMP() is an aggregate function, and so it can be used with the GROUP BY clause.

The VAR_SAMP() function can also be used as a window function.

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How VARIANCE() Works in MySQL

In MySQL, the VARIANCE() function returns the population standard variance of an expression.

If there are no matching rows, or if the expression is NULL, the function returns NULL.

The VARIANCE() function is a synonym for the standard SQL VAR_POP() function. In other words, they both do the same thing, but VARIANCE() is not standard SQL. Therefore, if you need to use standard SQL, use VAR_POP() instead.

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Understanding the VAR_POP() Function in MySQL

In MySQL, the VAR_POP() function returns the population standard variance of an expression.

If there are no matching rows, or if the expression is NULLVAR_POP() it returns NULL.

VAR_POP() is an aggregate function, and so it can be used with the GROUP BY clause.

The VAR_POP() function is standard SQL. There’s also a VARIANCE() function that does the same thing, but is not standard SQL.

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Understanding the STDDEV_SAMP() Function in MySQL

In MySQL, the STDDEV_SAMP() function returns the sample standard deviation of a given expression. This is the square root of VAR_SAMP().

STDDEV_SAMP() is an aggregate function, and so it can be used with the GROUP BY clause.

If there are no matching rows, or if the expression is NULL, STDDEV_SAMP() returns NULL.

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