Why is the equal sign not working in SQL, where as same dates are being extracted with greater than-CodePudding

I want to extract customers created on 2021-10-14 (yyyy-mm-dd),

select * from customers where created_at = '2021-10-14'

This is giving 0 rows as output. Whereas this code is showing the data created on 2021-10-14:

select * from customers where created_at > '2021-10-14' and created_at < '2021-10-15'

why is equal to not working in the above query and why is greater than including the given date.

CodePudding user response：

Probably because your created_at column is of type datetime. And for instance a created time of

'2021-10-14 12:00:00'

is not not the same as

'2021-10-14'

because it is actually comparing the time value too which is

'2021-10-14 00:00:00'

The query you used (with the fixed typo of >=) is actually the correct way to go since it is able to use indexes for better performance

select * 
from customers 
where created_at >= '2021-10-14' 
  and created_at < '2021-10-15'