What does the vertical pipe slash operator do?

Question

I'm wondering what pipe slash |/ does in,

SET equal_area_radius = |/area/pi();

The statement works and it definitely changes the value:

SELECT |/125.555/pi(); --  returns: 6.32181918120139
SELECT 125.555/pi();   --  returns: 39.9653977598058

What does the pipe-slash operator |/ do?

user1822user1822 · Accepted Answer · 2019-01-09 13:30:41Z

5

The |/ operator calculates the square root

postgres>  select |/16,  sqrt(16);
 ?column? | sqrt
----------+------
        4 |    4
(1 row)

So |/125.555/pi() is equivalent to sqrt(125.555/pi())

answered Jan 9, 2019 at 13:30

user1822

Sure enough--looked at the site where I copied the statement from and they had this: i.imgur.com/5twDykK.png I should have worked that one out. Thanks!
– Jay Cummins
Jan 9, 2019 at 13:41
1

@a_horse funny that the |/ operator has lower precedence than / an *.
– ypercubeᵀᴹ
Jan 9, 2019 at 15:01
it makes sense. in math, the radical symbol, which |/ is supposed to suggest, is often used with a long expression underneath it. this would only work if |/ has low precedence.
– Ross Presser
Jan 17, 2019 at 4:09

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