Tag: databases

Questions Related to databases

Which SQL statement is used to insert new data in a database?

technology databases

  1. INSERT NEW

  2. ADD NEW

  3. ADD RECORD

  4. INSERT INTO

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Correct Option: D

AI Explanation

To answer this question, you need to understand SQL statements for inserting new data into a database.

Let's go through each option to understand why it is correct or incorrect:

Option A) INSERT NEW - This option is incorrect because there is no SQL statement called "INSERT NEW" for inserting new data into a database.

Option B) ADD NEW - This option is incorrect because there is no SQL statement called "ADD NEW" for inserting new data into a database.

Option C) ADD RECORD - This option is incorrect because there is no SQL statement called "ADD RECORD" for inserting new data into a database.

Option D) INSERT INTO - This option is correct because the SQL statement "INSERT INTO" is used to insert new data into a database.

The correct answer is D) INSERT INTO. This option is correct because the "INSERT INTO" statement is commonly used in SQL to add new records to a database table.

With SQL, how do you select a column named 'FirstName' from a table named 'Persons'?
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  1. SELECT FirstName FROM Persons

  2. EXTRACT FirstName FROM Persons

  3. SELECT Persons.FirstName

  4. SELECT * FROM Persons

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Correct Option: A

Which SQL statement is used to delete data from a database?

technology databases

  1. COLLAPSE

  2. REMOVE

  3. DELETE

  4. TRUNCATE

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Correct Option: C

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

  1. SELECT [all] FROM Persons

  2. SELECT * FROM Persons

  3. SELECT *.Persons

  4. SELECT Persons

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Correct Option: B
Explanation:

To select all the columns from a table named 'Persons' using SQL, the user needs to use the following query:

B. SELECT * FROM Persons

Option A is incorrect because the SQL keyword for selecting all columns is not 'all,' but rather '*'.

Option C is incorrect because the '*' should come before the table name, and not after it.

Option D is incorrect because 'Persons' alone does not specify which columns to select from the table.

Therefore, the correct answer is option B.

With SQL, how do you select all the records from a table named 'Persons' where the value of the column 'FirstName' is 'Peter'?

technology databases

  1. SELECT * FROM Persons WHERE FirstName <> 'Peter'

  2. SELECT [all] FROM Persons WHERE FirstName='Peter'

  3. SELECT [all] FROM Persons WHERE FirstName LIKE 'Peter'

  4. SELECT * FROM Persons WHERE FirstName='Peter'

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Correct Option: D
Explanation:

To select all the records from the table named 'Persons' where the value of the column 'FirstName' is 'Peter', the correct SQL query is:

D. SELECT * FROM Persons WHERE FirstName='Peter'

Let's go through each option and explain why the other options are incorrect:

A. SELECT * FROM Persons WHERE FirstName <> 'Peter' This query selects all records where the 'FirstName' column is not equal to 'Peter'. It is the opposite of what we want, so this option is incorrect.

B. SELECT [all] FROM Persons WHERE FirstName='Peter' The use of '[all]' is not necessary in this query. It should be replaced with '*' to select all columns. Additionally, the operator '=' should be used instead of 'LIKE' since we are looking for an exact match. Therefore, this option is incorrect.

C. SELECT [all] FROM Persons WHERE FirstName LIKE 'Peter' The 'LIKE' operator is used for pattern matching and allows the use of wildcards (% or _). Since we are looking for an exact match of 'Peter', the '=' operator should be used instead. Therefore, this option is incorrect.

D. SELECT * FROM Persons WHERE FirstName='Peter' This option correctly selects all records from the 'Persons' table where the 'FirstName' column is equal to 'Peter'.

So, the correct answer is: D. SELECT * FROM Persons WHERE FirstName='Peter'

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 LIKE '%a'

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

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

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Correct Option: A

Which SQL statement is used to return only different values?
technology databases

  1. SELECT DISTINCT

  2. SELECT DIFFERENT

  3. SELECT UNIQUE

  4. SELECT ALL

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Correct Option: A

Which SQL keyword is used to sort the result-set?
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  1. ORDER

  2. ORDER BY

  3. SORT BY

  4. SORT

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Correct Option: B

With SQL, how can you return all the records from a table named 'Persons' sorted descending by 'FirstName'?
technology databases

  1. SELECT * FROM Persons ORDER FirstName DESC

  2. SELECT * FROM Persons ORDER BY FirstName DESC

  3. SELECT * FROM Persons SORT BY 'FirstName' DESC

  4. SELECT * FROM Persons SORT 'FirstName' DESC

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Correct Option: B
Explanation:

To solve this question, the user needs to know SQL syntax and the concept of sorting query results in a descending order based on a specific column.

Now, let's go through each option and explain why it is right or wrong:

A. SELECT * FROM Persons ORDER FirstName DESC This option is incorrect because the correct syntax for sorting query results in SQL requires the use of the "ORDER BY" clause followed by the column name to sort by, and then the keyword "DESC" to specify descending order. Therefore, the correct syntax should be "ORDER BY FirstName DESC" instead of "ORDER FirstName DESC".

B. SELECT * FROM Persons ORDER BY FirstName DESC This option is correct. The "ORDER BY" clause is used to sort the query results based on a specific column. In this case, we want to sort the results in descending order based on the "FirstName" column. Therefore, the correct syntax is "ORDER BY FirstName DESC".

C. SELECT * FROM Persons SORT BY 'FirstName' DESC This option is incorrect because there is no "SORT" keyword in SQL. The correct keyword to use is "ORDER BY". Additionally, the column name should not be enclosed in single quotes. Therefore, the correct syntax should be "ORDER BY FirstName DESC" instead of "SORT BY 'FirstName' DESC".

D. SELECT * FROM Persons SORT 'FirstName' DESC This option is incorrect because the correct keyword to use for sorting query results in SQL is "ORDER BY" rather than "SORT". Additionally, the column name should not be enclosed in single quotes. Therefore, the correct syntax should be "ORDER BY FirstName DESC" instead of "SORT 'FirstName' DESC".

The Answer is: B

What is the output? SELECT SUBSTRING('123456', 0, 3)
technology databases

  1. 123

  2. 12

  3. 123456

  4. 456

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Correct Option: B