Quiz 4 Flashcards
When you code a union that combines two result sets, which of the following is not true?
duplicate rows in the result set are allowed *
each result set must have the same number of columns *
the result sets must be derived from different tables
the corresponding columns in the result sets must have compatible data types
3rd one??
A full outer join includes rows that satisfy the join condition, plus ___________
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rows in the right table that don’t satisfy the join condition
the Cartesian product of the two tables
rows in both tables that don’t satisfy the join condition
rows in the left table that don’t satisfy the join condition
rows in both tables that don’t satisfy the join condition
- Table aliases are temporary table names assigned in which clause?
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FROM
ORDER BY
ON
WHERE
FROM
In most cases, the join condition of an inner join compares the primary key of one table to the ____________________ key of another table
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primary
SELECT
foreign
unique
foreign
The bringing together of rows from two tables.
Join
Specifies how the rows of table A are to be brought together with the rows of table B.
Join Condition
For an inner join (defalut type) only rows from table A and table B that satisfy the join condition are placed on the table C. If rows exist in table A and/or table B that do not satify the join condition, these rows will not be present in table C.
Inner Join
A fully qualified name consists of four parts: a server name, a database name, a schema name, and the name of the object itself. At times it will be necessary to qualify a column name (either partially or fully) to tell SQL server the source of the column.
Qualified Column Name
The join syntax introduced in the SQL-92 standard.
explicit syntax
Temporary table names assigned in the FROM clause.
correlation name or table alias
A join where a table is joined to itself.
self-join
Pre SQL92 join Syntax.
implicit syntax
A join in which all the rows of a table appear in the join results, regardless of whether they have a match in the join condition.
Outer Join
All of the rows in the left table appear in the join results, regardless of whether they have a match in the join condition.
Left Outer Join
All of the rows in the right table appear in the join results, regardless of whether they have a match in the join condition.
Right Outer Join
All of the rows in both joined tables appear in the join results regardless of whether they have a match in the join condition.
Full Outer Join
Each row from table A is joined (concatenated) with each row from table B.
Cross Join (Cartesian Product)
Combining the results of two or more SELECTS that return the same number of corresponding columns.
Union
A union combines the rows from two or more _______
SELECT statements
string expressions
databases
tables
SELECT statements
If you assign an alias to one table in a join, you have to _________
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use that name for the table in the query
assign one to all of the tables in the query
qualify every column name in the query
qualify all of the column names for that table
use that name for the table in the query
In a join, column names only need to be qualified where?
in inner joins
when the code is confusing
in outer joins
when the same column names are used in both tables
when the same column names are used in both tables
SELECT VendorName AS Vendor, InvoiceDate AS Date
FROM Vendors v JOIN Invoices i ON v.VendorID = i.VendorID;
This type of join is called _________________________
a left join
a right join
an inner join
an outer join
an inner join
?
