This set of SQL Multiple Choice Questions & Answers (MCQs) focuses on “SQL Aliases”.
1. Temporary names given to a table or a column for the purpose of a particular SQL query are known as __________
a) Aliases
b) Temp
c) Temporary
d) Rename
View Answer
Explanation: The use of table aliases is to rename a table in a specific SQL statement. SQL ALIASES can be used to create a temporary name for columns or tables.
2. An SQL ALIAS exists even after the execution of a query.
a) True
b) False
View Answer
Explanation: Using SQL ALIAS we can rename a column or a table temporarily. An alias exists only during the execution of the query. After its execution those temporary names cannot be used as the changes are not permanent in the database.
3. Which of the following is used to rename a table or a column in a specific SQL statement?
a) Rename
b) Change
c) Alias
d) Modify
View Answer
Explanation: The alias is used to rename a table or a column in a specific SQL statement. The renaming is a temporary change and the actual table name or column name does not change in the database.
4. What is the basic syntax for a column alias?
a)
SELECT column_name AS alias_name FROM TABLE_NAME;
b)
SELECT column_name ALIAS alias_name FROM TABLE_NAME;
c)
SELECT column_name COLUMN ALIAS alias_name FROM TABLE_NAME;
d)
SELECT column_name COLUMN AS alias_name FROM TABLE_NAME;
Explanation: Aliases are the temporary names given to table or column for the purpose of a particular SQL query. Basic syntax for a column alias is:
SELECT column_name AS alias_name FROM TABLE_NAME;
5. What is the basis syntax for a table alias?
a)
SELECT column_name FROM TABLE_NAME ALIAS alias_name;
b)
SELECT column_name FROM TABLE_NAME TABLE AS alias_name;
c)
SELECT column_name FROM TABLE_NAME AS alias_name;
d)
SELECT column_name FROM TABLE_NAME TABLE ALIAS alias_name;
Explanation: SQL ALIASES can be used to create a temporary name for columns or tables. Basic syntax for a table alias is:
SELECT column_name FROM TABLE_NAME AS alias_name;
6. Alias name should not contain any spaces.
a) True
b) False
View Answer
Explanation: It is acceptable to use spaces in an alias name. If the alias name contains spaces, we must enclose the alias name in double quotes or square brackets. This alias name is only valid within the scope of the SQL statement.
7. ALIAS can be used with which of the following clause(s)?
a) Insert
b) Update
c) Select
d) Delete
View Answer
Explanation: Aliases are the temporary names given to table or column for the purpose of a particular SQL query. It can be used with SELECT clause of a query. We cannot use ALIAS with insert, update or delete clauses.
8. When creating table aliases _______
a) It is not necessary to create aliases for all of the tables listed in the FROM clause
b) It is necessary to create aliases for at least two of the tables listed in the FROM clause
c) It is necessary to create aliases for all of the tables listed in the FROM clause
d) It is necessary to create aliases for at least three of the tables listed in the FROM clause
View Answer
Explanation: When creating table aliases, it is not necessary to create aliases for all of the tables listed in the FROM clause. We can choose to create aliases on any or all of the tables.
9. During the execution of a query, the temporary names of columns or tables can be used for ______
a) Only one time
b) Specified number of times
c) Any number of times
d) Maximum three times
View Answer
Explanation: The temporary names of columns or tables can be used for any number of times within the specified query.
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