Verify your knowledge

• If we run this query and data on the table called mytable is not changed, do we always get the same result?

  select * from mytable
  

  No, we don’t, because the ordering of the data could be different.

  See the section Exploring the SELECT statement for more details.

• Is it possible to have only 3 records as result of a query?

  Yes, it’s possible using the LIMIT clause.

  See the section Using limit and offset for more details.

• If we have 2 tables: table A with 3 records with a field id as the primary key, and table B with 2 records with a field id as the primary key, what kind of join do we have to use to match all the records that have the same ID on table A and table B?

  We have to use an inner join query:

  select tableA.id from tableA inner join tableB using(id)
  

  See the section Using INNER JOIN for more details.

• If we have 2 tables...