In PostgreSQL, the setseed() function sets the seed for subsequent random() and random_normal() calls (value between -1.0 and 1.0, inclusive).

The random() function generates a pseudo-random number using a simple linear congruential algorithm. The random_normal() function generates a normally-distributed random number.

If setseed() is called, the results of subsequent random() and random_normal() calls in the current session are repeatable by re-issuing setseed() with the same argument.

Continue reading →

In PostgreSQL, the random() function returns a pseudo-random value in the range 0.0 <= x < 1.0.

It uses a simple linear congruential algorithm, which is one of the oldest and best-known pseudo-random number generator algorithms.

A pseudo-random number is a number that appears to be random, but is not truely random. A pseudo-random number is not truely random because its value was generated by a known seed. However, it will appear to be random if the user has no knowledge of the seed or algorithm that created it.

Therefore, pseudo-random numbers are often considered good enough for many applications.

Continue reading →

In PostgreSQL, cot() is a trigonometric function that returns the cotangent of the specified angle.

The angle is provided as an argument, specified in radians.

In trigonometry, in a right triangle, the cotangent of an angle is the length of the adjacent side divided by the length of the opposite side.

Continue reading →

In PostgreSQL, cotd() is a trigonometric function that returns the cotangent of the specified angle.

The angle is provided as an argument, specified in degrees.

In trigonometry, in a right triangle, the cotangent of an angle is the length of the adjacent side divided by the length of the opposite side.

Continue reading →

In PostgreSQL, atan2() is a trigonometric function that returns the arctangent, or inverse tangent, of the specified x and y coordinates in radians.

Continue reading →

In PostgreSQL, atan2d() is a trigonometric function that returns the arctangent, or inverse tangent, of the specified x and y coordinates in degrees.

Continue reading →

In PostgreSQL, atan() is a mathematical function that returns the angle, in radians, whose tangent is a specified expression.

In trigonometry, this is known as the arctangent. The arctangent is the inverse of the tangent.

The arctangent is used when you know what the tangent of an angle is, but you want to know what the actual angle is.

Continue reading →

In PostgreSQL, atan() is a mathematical function that returns the angle, in degrees, whose tangent is a specified expression.

In trigonometry, this is known as the arctangent. The arctangent is the inverse of the tangent.

The arctangent is used when you know what the tangent of an angle is, but you want to know what the actual angle is.

Continue reading →

In PostgreSQL, tan() is a mathematical function that returns the tangent of the input expression.

The input expression is provided as an argument, and it is specified in radians.

In trigonometry, in a right-angled triangle, the tangent of an angle is the length of the opposite side divided by the length of the adjacent side.

Continue reading →

In PostgreSQL, tan() is a mathematical function that returns the tangent of the input expression.

The input expression is provided as an argument, and it is specified in degrees.

In trigonometry, in a right-angled triangle, the tangent of an angle is the length of the opposite side divided by the length of the adjacent side.

Continue reading →