This is personal study note
Copyright and original reference:
https://www.youtube.com/watch?v=7UpsG6_HoI0&list=PLVsNizTWUw7HhYtI-4GGmlJ5yxNdwNI_X
================================================================================
================================================================================
use between and
================================================================================
simpler by using where in ()
================================================================================
% wildcard
_ wildcard
================================================================================
Use sub query for super query
================================================================================
In drag sentence, it must have one number, in that case, it's 2 numbers which are returned from that sub query
To resolve it, use any
================================================================================
order by height --> order by name
"order by" should be avoided in use due to high computational cost
unless it's inevitably required
================================================================================
remove duplicates in the result (useful)
================================================================================
quiry 5 employees who have worked for longest period
This shows 300000 records
By using Limit, you can cut the result
longest employeement period: 100 to 105 employees
================================================================================
Create table
It's kind of "copy table buyTbl to buyTbl2"