Chapter 4 SQL test
You can combine inner and outer joins within a single _______________ statement.
Select
A union combines the rows from two or more _______________________.
Select-statements
When you code a union that combines two result sets, which of the following is not true?
The result sets must be derived from different tables.
When you use the implicit syntax for coding joins, the join conditions are coded in the ____________ clause.
WHERE
You can simulate a full outer join by using
a union
A table ___________________ can be used when you want to assign a temporary name to a table.
alias
SELECT vendor_name, invoice_date FROM vendors v JOIN invoices i ON v.vendor_id = i.vendor_id (Refer to code example 4-1.) The "v" in this example is known as a/an ____________________________________.
alias
Like a join, a union combines data from two or more tables. But, instead of combining columns from base tables, a union
combines the result sets of two or more SELECT statements
In most cases, the join condition of an inner join uses the _______________ operator to compare two keys
equal
SELECT vendor_name, invoice_date FROM vendors v JOIN invoices i ON v.vendor_id = i.vendor_id (Refer to code example 4-1.) This join is coded using the _____________________________ syntax.
explicit
In most cases, the join condition of an inner join compares the primary key of one table to the ____________________ key of another table.
foreign
SELECT vendor_name, invoice_date FROM vendors v JOIN invoices i ON v.vendor_id = i.vendor_id (Refer to code example 4-1.) This type of join is called a/an __________________ join.
inner
Which of the following is not a reason for using the explicit syntax instead of the implicit syntax for joins? The explicit syntax
is an older syntax that works with legacy code
In a cross join, all of the rows in the first table are joined with all of the
rows from the second table
If you want to join all of the rows in the first table of a SELECT statement with just the matched rows in a second table, you use a/an _______________ join.
self
When you use the USING keyword for a join,
the join must be based on a column or columns that have the same name in both tables
SELECT vendor_name, invoice_number FROM invoices LEFT JOIN vendors ON invoices.vendor_id = vendors.vendor_id
the number of rows in the invoices table
A full outer join returns
unmatched rows from both the left and right tables
If you assign an alias to one table in a join, you have to
use that alias to refer to the table throughout your query
In a join, column names need to be qualified only
when the same column names exist in both tables
Which is not true about the USING keyword
you code a USING clause in addition to the ON clause