Basic Tools of SQL 1-1

What is SQL?

• It's a language used to talk to the database.
• You send queries to get the data you want

Basic commands: Select,From,*

• select: used to call any and all data in SQL
• from: specifies the data table we plan to get from the query
• *: indicates we are getting all
• the code below calls all the columns from food orders data base/table

select *
from food_orders

Getting specific columns only

select restaurant_name, addr
from food_orders

How to give temporary “alias” to columns/variables

• Method1: using double quotes
• Method2: simply writing it after a space

select restaurant_name as "음식점", addr address
from food_orders

• For non-English alias, you need to use the double quotes method
• ‘as’ is optional

Filtering using WHERE

select *
from food_orders fo
where cuisine_type='Korean'

• Result
  
• You can use 'and' to add further filters!

select *
from food_orders fo
where cuisine_type='Korean' and quantity>=3