In MySQL, the STD() function returns the population standard deviation of a given expression.
STD() is a synonym for the standard SQL function STDDEV_POP(). There’s also a STDDEV() function which also does the same thing, so we can use either of these functions to get the same result.
In MySQL, the BIT_XOR() function returns the bitwise XOR of all bits in a given expression.
XOR is an exclusive OR, and so a XOR b is mathematically equal to (a AND (NOT b)) OR ((NOT a) and b).
In MySQL, the BIT_OR() function returns the bitwise OR of all bits in a given expression.
In MySQL, the BIT_AND() function returns the bitwise AND of all bits in a given expression.
The SQLite json_group_object() function is an aggregate function that returns a JSON object comprised of all name/value pairs in the aggregation.
In other words, it constructs a JSON object from the values provided by its arguments.
The SQLite json_group_array() function is an aggregate function that returns a JSON array comprised of all values in the aggregation.
In other words, it constructs an array from the values provided by its argument.
In PostgreSQL, the SUM() function computes the sum of the non-null input values and returns the result.
In other words, it adds numbers and returns the result.
In PostgreSQL, the AVG() function computes the average (arithmetic mean) of all the non-null input values, and returns the result.
In PostgreSQL, the MAX() function computes the maximum of the non-null input values and returns the result.
This function can be used on any numeric, string, date/time, or enum type, as well as inet, interval, money, oid, pg_lsn, tid, and arrays of any of these types.
In PostgreSQL, the MIN() function computes the minimum of the non-null input values and returns the result.
This function can be used on any numeric, string, date/time, or enum type, as well as inet, interval, money, oid, pg_lsn, tid, and arrays of any of these types.