Tag: databases

Questions Related to databases

Which SQL statement is used to return only different values?

technology databases

  1. SELECT DIFFERENT

  2. SELECT DISTINCT

  3. SELECT UNIQUE

  4. SELECT PRIMARY

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Correct Option: B

With SQL, how do you select all the records from a table named "Persons" where the value of the column "FirstName" starts with an "a"?

technology databases

  1. SELECT * FROM Persons WHERE FirstName LIKE '%a'

  2. SELECT * FROM Persons WHERE FirstName='a'

  3. SELECT * FROM Persons WHERE FirstName LIKE 'a%'

  4. SELECT * FROM Persons WHERE FirstName='%a%'

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Correct Option: C

AI Explanation

To select all the records from a table named "Persons" where the value of the column "FirstName" starts with an "a", you can use the SQL query:

Option C) SELECT * FROM Persons WHERE FirstName LIKE 'a%'

Explanation for each option:

Option A) SELECT * FROM Persons WHERE FirstName LIKE '%a' This option is incorrect because the '%a' wildcard pattern at the end will match any value that ends with 'a', not just those that start with 'a'.

Option B) SELECT * FROM Persons WHERE FirstName='a' This option is incorrect because it will only select the records where the value of the column "FirstName" is exactly 'a', not those that start with 'a'.

Option C) SELECT * FROM Persons WHERE FirstName LIKE 'a%' This option is correct because the 'a%' wildcard pattern at the end will match any value that starts with 'a'. This is the correct way to select all the records where the value of the column "FirstName" starts with 'a'.

Option D) SELECT * FROM Persons WHERE FirstName='%a%' This option is incorrect because the '%a%' wildcard pattern on both sides will match any value that contains 'a', not just those that start with 'a'.

The correct answer is Option C) SELECT * FROM Persons WHERE FirstName LIKE 'a%'. This option is correct because it selects all the records where the value of the column "FirstName" starts with 'a'.

With SQL, how do you select all the columns from a table named "Persons"?
technology databases

  1. SELECT [all] FROM Persons

  2. SELECT Persons

  3. SELECT *.Persons

  4. SELECT * FROM Persons

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Correct Option: D

Which two are attributes of iSQL*Plus? (Choose two)
technology databases

  1. iSQL*Plus commands manipulate table definitions in the database.

  2. iSQL*Plus is the Oracle proprietary interface for executing SQL statements.

  3. iSQL*Plus commands cannot be abbreviated.

  4. iSQL*Plus commands are accesses from a browser.

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Correct Option: B,D

You need to perform certain data manipulation operations through a view called EMP_DEPT_VU, which you previously created. You want to look at the definition of the view (the SELECT statement on which the view was create.) How do you obtain the definition of the view?
technology databases

  1. Use the DESCRIBE command in the EMP_DEPT VU view.

  2. Use the DEFINE VIEW command on the EMP_DEPT VU view.

  3. Query the USER_VIEWS data dictionary view to search for the EMP_DEPT_VU view.

  4. Query the USER_SOURCE data dictionary view to search for the EMP_DEPT_VU view.

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Correct Option: C

Which is an /SQL*Plus command?
technology databases

  1. insert

  2. update

  3. select

  4. describe

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Correct Option: D

Evaluate this SQL statement: SELECT e.EMPLOYEE_ID,e.LAST_NAME,e.DEPARTMENT_ID, d.DEPARTMENT_NAME. FROM EMP e, DEPARTMENT d WHERE e.DEPARTMENT_ID = d.DEPARTMENT_ID; In the statement, which capabilities of a SELECT statement are performed?
technology databases

  1. Selection, projection, join

  2. Difference, projection, join

  3. Selection, intersection, join

  4. Intersection, projection, join

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Correct Option: A

:new can be used in stament level trigger
technology databases

  1. True

  2. False

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Correct Option: B

Order by cause should be used only at end of query
technology databases

  1. True

  2. False

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Correct Option: A

union all is faster than union
technology databases

  1. True

  2. False

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Correct Option: A