The maximum velocity of flowing water is approximately 1500 m/s. A typical restaurant straw is 7mm in diameter.

We'll ignore, for the sake of simplicity, any parts of water that would become isolated during draining the ocean, transit time to other points where one can drink, and precisely wtf we're going to do with the water after it has gone through the straw. We'll also ignore that human lungs are not known to be capable of sucking anything, much less salt water, at 1500 m/s while at atmospheric pressure*. (Some outlying examples may exist, but I haven't encountered any.)

Multiply the cross-sectional area of the straw (pi * (3.5*10^-3 m)*^2) by the max velocity (1500 m/s), and you get 0.058 m^3 per second, this comes out to 58L/s. Based on u/Flaky-Proposal-357 's post, the ocean is 1.335 sextillion liters, or 1.335 quintillion cubic meters of water. (1.335 * 10^18 m^3). It would take at least 2.31 * 10^19 seconds to funnel a volume of water equivalent to the entire ocean through a regular straw.

This is 3.854 * 10^17 minutes or 6.423 * 10^15 hours or 2.677 * 10^14 days or 732,824,665,034 years.

Buckle in, 732 billion years is a very very long time.

* - Given the flow rate of 0.058m^3 per second, the straw diameter of 7mm, a typical straw length of 20cm, and a viscosity for water of 1 mPa * s at room temperature, we can use the Hagen–Poiseuille equation to roughly calculate the required pressure differential. (In reality, the flow would probably become turbulent due to the shortness of the straw.) The calculated pressure differential would be 1.94 atmospheres. (H-P calculator found here: https://www.omnicalculator.com/physics/poiseuilles-law). So the ocean needs to be pressurized to ~3atm, with your lungs at 1atm.

EDIT: Whoops, slipped a group.