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Perguntas do quiz (12)
1In a join, column names need to be qualified only:
- Ain inner joins
- Bin outer joins
- Cwhen the code is confusing
- Dwhen the same names are used in both tables
2If you assign a correlation name to one table in a join,
- Ayou have to assign them to all of the tables
- Byou have to use that name for the table
- Cyou have to qualify every column name in the query
- Dyou have to qualify all of the column names for that table
3When you need to code multiple conditions in a join, its best to:
- Acode all conditions in the ON clause
- Bcode only join conditions in the ON clause
- Ccode all conditions in the WHERE clause
- Dcode only join conditions in the WHERE clause
4You don’t ever need to code a right outer join because:
- Aleft outer joins are just as efficient
- Bleft outer joins are easier to code
- Cright outer joins are less efficient
- Dright outer joins can be converted to left outer joins
5Which of the following is not a reason for using the explicit syntax instead of the implicit syntax for joins? The explicit syntax:
- Ais easier to read and understand
- Blets you separate the join and search conditions
- Ccan be used for more than two tables
- Dlets you combine inner and outer joins
6In a cross join, all of the rows in the first table are joined with all of the:
- Adistinct rows in the second table
- Bmatched rows in the second table
- Cunmatched rows in the second table
- Drows in the second table
7When you code a union that combines two result sets, which of the following is not true?
- AEach result set must have the same number of columns.
- BThe result sets may or may not have any duplicate rows.
- CThe corresponding columns in the result sets must have compatible data types.
- DThe result sets must be derived from different tables.
8When you code a union with the INTERSECT keyword to combine two result sets, the union:
- Aincludes only rows that occur in both result sets
- Bexcludes rows from the first result set if they also occur in the second result set
- Cincludes all rows that occur in both result sets if the primary keys are the same
- Dexcludes rows from the second result set if they also occur in the first result set
9A full outer join includes rows that satisfy the join condition, plus:
- Arows in the left table that don’t satisfy the join condition
- Brows in both tables that don’t satisfy the join condition
- Crows in the right table that don’t satisfy the join condition
- Dthe Cartesian product of the two tables
10SELECT VendorName, InvoiceNumber
FROM Invoices LEFT JOIN Vendors
ON
Invoices.VendorID = Vendors.VendorID
The total number of rows returned by this query must equal:- Athe number of rows in the Invoices table
- Bthe number of rows in the Vendors table
- Cthe number of rows in the Invoices table plus the number of rows in the Vendors table
- Dnone of the above
11SELECT VendorName, InvoiceNumber
FROM Invoices LEFT JOIN Vendors
ON
Invoices.VendorID = Vendors.VendorID
If the LEFT keyword is replaced with the RIGHT keyword, the total number of rows that are returned must equal:- Athe number of rows in the Invoices table
- Bthe number of rows in the Vendors table
- Cthe number of rows in the Invoices table plus the number of rows in the Vendors table
- Dnone of the above
12SELECT VendorName, InvoiceNumber
FROM Invoices LEFT JOIN Vendors
ON
Invoices.VendorID = Vendors.VendorID
If the LEFT keyword is replaced with the FULL keyword, the total number of rows that are returned must equal- Athe number of rows in the Invoices table
- Bthe number of rows in the Vendors table
- Cthe number of rows in the Invoices table plus the number of rows in the Vendors table
- Dnone of the above
Informações
- Descrição
- Quiz sobre Sem título, criado por CJ Correll em 08-11-2019.
- Autor
- CJ Correll
- Idioma
- English
- Visualizações
- 0
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