SQL Statement 2

SQL statements 2

Update, alter, drop statement

SQL ALTER TABLE Statement

The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.

The ALTER TABLE statement is also used to add and drop various constraints on an existing table.

We will modify and add a column called City to our table

Now we will check

We will update the city for everyone

We will confirm and now everyone just moved to Miami!

We will move one user to Tampa: Alex Rodriguez

We will verify

Now we will drop this table

Now we will create another table with a primary key and identity 1,1 so they will be added automatically

the results is positive as we can see..

Now we will create two tables:  Product table and FoodOrder Table

Now the Food Order table:

Now we will inset some data into the table

Now let 's run some information because one of the players was hungry

Pedro Martinez got some fries!

Now create several orders in the same way..altering the numbers and executing them

So, who buy what and what is the total amount?


Let's double check ourt tables values first

SQL PRIMARY KEY Constraint

The PRIMARY KEY constraint uniquely identifies each record in a database table.

Primary keys must contain UNIQUE values, and cannot contain NULL values.

A table can have only one primary key, which may consist of single or multiple field

Check the keys in our table

SQL INNER JOIN Keyword

The INNER JOIN keyword selects records that have matching values in both tables.

Now let's join our tables together  !

We will execute and this is the positive results..

WE can use an "alias."..

and simplify more than that..

let's make this table shorter!

The SQL GROUP BY Statement

The GROUP BY statement is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns.

We will try to find out the total amount of money spend

We can find out how much each one spends

And we can do that by City

So, we can see there is a lot of function in SQL...

I hope that you enjoy this lab..
In case that you have any questions, Please don't hesitate to ask