Re: storing deleted appoitments

[Rick James]

How to store a boolean...

deleted TINYINT UNSIGNED NOT NULL COMMENT '0=false=active, 1=true=deleted'
WHERE deleted
WHERE NOT deleted
(BOOL works the same)

active TINYINT UNSIGNED NOT NULL COMMENT '0=false=deleted, 1=true=active'
WHERE active
WHERE NOT active
(BOOL works the same)

status ENUM('deleted', 'active') NOT NULL
WHERE status = 'deleted'
WHERE status = 'active'

status CHAR(1) NOT NULL CHARSET=ascii COMMENT 'D=deleted, A=active'
WHERE status = 'D'
WHERE status = 'A'

Each takes 1 byte of storage.
Performance of each is virtually identical.
So, think about how you want to phrase the WHERE clause.

If you have more than two values, BOOL fails and TINYINT needs a number:
WHERE deleted=0 -- no
WHERE deleted=1 -- yes
WHERE deleted=2 -- maybe

The `status` examples expand to more than 2 choices in an obvious way. However, I would not go beyond a few dozen values; it gets cumbersome (as would TINYINT).