MySQL must know to learn

MySQL must know

First, there's a table.

Customer table: Product table:

Order Element table: Product record table:

Order Form:

Seller Table:

16th. Creating an advanced junction

Select concat (rtrim(vend_name),'(',RTrim(vend_country), ' )'as fromorder by Vend_name;

There are two benefits of using aliases:

1. Shorten the SQL statement

2. Allow the same table to be used multiple times in a single SELECT statement

Use different types of junctions

1. Self-coupling

Connect yourself to the table

Select  from  as  as where =  and = ' dtntr '

As you can see from the code above: Use table aliases to correlate tables with each other

2. Natural coupling

Joins between tables based on the fields between each table

Select c.*from as aswhere= and =  and = ' FB '

3. External coupling

MySQL must know to learn