20761C:Querying Data with Transact-SQL 2016 Quiz Questions and Answers
When is the wildcard in a WHERE clause useful?
Answer :
When an exact match is not possible in a SELECT statement
Explanation :
The wildcard is a character used to search complex data from the database quickly. We can use it in conjunction with the LIKE or NOT LIKE comparison operators and the WHERE clause to find the result for a specified pattern. Hence, the wildcard is very use
Which of the following are the basic approaches for joining tables?
Answer :
A) CROSS JOIN B) OUTER JOIN C) INNER JOIN All of the above
Explanation :
We already know that Union and Natural are the approaches for joining two or more tables. A subquery is a query nested into another SQL query. It can be embedded with SELECT, INSERT, UPDATE or DELETE statement. A subquery is known as the inner query. In m
Which type of JOIN is used to return rows that do not have matching values?
Answer :
OUTER JOIN
Explanation :
OUTER JOIN is the only join that returned the unmatched rows in one or both tables. It can be classified into the following types:
LEFT JOIN that shows only the unmatched rows from the left table.
RIGHT JOIN that shows only the unmatched rows from the ri
Which command is used to change the definition of a table in SQL?
Answer :
ALTER
Explanation :
The ALTER statement is used to change our table's definition, such as table name, column name, column constraint, etc. It also allows us to add or delete an existing column in a table. This statement must be used with ADD, DROP, and MODIFY clauses accordi
How can you change "Thomas " into "Michel " in the "LastName " column in the Users table?
Answer :
UPDATE Users SET LastName = 'Michel' WHERE LastName = 'Thomas'
Explanation :
The UPDATE statement is used for modifying the table data by using the SET and WHERE clause. The SET clause is used to change the values of the column specified in the WHERE clause. See the below syntax: UPDATE table SET column1 = expression1, column2
Which of the following is also called an INNER JOIN?
Answer :
EQUI JOIN
Explanation :
The INNER JOIN returns data from the two or more tables that match the specified condition and hides other records. EQUI JOIN is similar to INNER JOIN that returns records for equality or matching column(s) values of the relative tables.
If we have not specified ASC or DESC after a SQL ORDER BY clause, which of the following is used by default?
Answer :
ASC
Explanation :
If we have not specified any sorting with the ORDER BY clause, SQL always uses the ASC as a default sorting order. SQL treats Null as the lowest possible values while sorting.
