To select all the records from a table named "Persons" where the value of the column "FirstName" is "Peter", you would use the following SQL query:

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

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

Option A) SELECT [all] FROM Persons WHERE FirstName='Peter' This option is incorrect because the keyword "all" is not needed to select all records. The asterisk (*) symbol is used to select all columns.

Option B) SELECT * FROM Persons WHERE FirstName LIKE 'Peter' This option is incorrect because the "LIKE" keyword is used for pattern matching, not for exact matches. In this case, we need an exact match, so the "=" operator should be used instead of "LIKE".

Option C) SELECT [all] FROM Persons WHERE FirstName LIKE 'Peter' Similar to Option A, this option is incorrect because the keyword "all" is not needed to select all records. The asterisk (*) symbol is used to select all columns.

Option D) SELECT * FROM Persons WHERE FirstName='Peter' This option is correct because it selects all columns (*) from the "Persons" table where the value of the "FirstName" column is exactly "Peter".

The correct answer is D.

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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 LIKE operator with the 'a%' pattern.

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

Option A) SELECT * FROM Persons WHERE FirstName='%a%' - This option is incorrect because the '%' wildcard should be placed at the end of the pattern to match any characters after 'a'.

Option B) SELECT * FROM Persons WHERE FirstName LIKE '%a' - This option is incorrect because the '%' wildcard should be placed at the beginning of the pattern to match any characters before 'a'.

Option C) SELECT * FROM Persons WHERE FirstName='a' - This option is incorrect because it only selects the records where the FirstName column has the exact value of 'a', not the ones that start with 'a'.

Option D) SELECT * FROM Persons WHERE FirstName LIKE 'a%' - This option is correct because it uses the '%' wildcard at the end of the pattern to match any characters after 'a', effectively selecting all the records where the FirstName column starts with 'a'.

Option E) SELECT * FROM Persons WHERE FirstName='a'" - This option is incorrect because it only selects the records where the FirstName column has the exact value of 'a', not the ones that start with 'a'.

The correct answer is Option D. This option is correct because it uses the LIKE operator with the 'a%' pattern to select all the records where the value of the column "FirstName" starts with an "a".

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To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) True - This option is correct because the OR operator displays a record if ANY of the conditions listed are true. In other words, if at least one of the conditions is true, the record will be displayed.

Option B) False - This option is incorrect because it contradicts the definition of the OR operator. The OR operator does not require all conditions to be true; it only requires at least one condition to be true.

The correct answer is A) True. This option is correct because it accurately describes the behavior of the OR operator.

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To determine the value that will be returned by the query select count(*) from employees, let's analyze the given employees table:

empid | name | managerid
------------------------
a1    | bob  | NULL
b1    | jim  | a1
B2    | tom  | a1

The query select count(*) from employees counts the number of rows in the employees table. It does not consider NULL values.

In this case, there are three rows in the table: (a1, bob, NULL), (b1, jim, a1), and (B2, tom, a1). Therefore, the query will return a value of 3.

Therefore, the correct answer is C) 3.

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To remove rows from a table in SQL, the correct statement to use is the DELETE statement. Let's go through each option to understand why it is correct or incorrect:

Option A) DROP - The DROP statement is used to delete an entire table or database, not specific rows within a table. Therefore, this option is incorrect.

Option B) REMOVE ROW - There is no specific SQL statement called REMOVE ROW. Therefore, this option is incorrect.

Option C) DELETE - The DELETE statement is used to remove one or more rows from a table based on a specific condition. It allows you to specify a WHERE clause to determine which rows should be deleted. This is the correct statement to use for removing rows from a table. Therefore, this option is correct.

Option D) DELETE ROW - There is no specific SQL statement called DELETE ROW. Therefore, this option is incorrect.

The correct answer is C) DELETE. This option is correct because the DELETE statement is used to remove one or more rows from a table based on a specific condition.

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To answer this question, you need to understand the different ways to join tables in SQL.

Option A) True - This option is incorrect because there are multiple ways to join tables in SQL, not just by using standard ANSI syntax. Other join types include INNER JOIN, OUTER JOIN (LEFT, RIGHT, FULL), CROSS JOIN, etc.

Option B) False - This option is correct because it acknowledges that the only way to join two tables is not limited to standard ANSI syntax. SQL provides various join types and syntax options to join tables based on the specific requirements of the query.

The correct answer is B) False. This option is correct because there are multiple ways to join tables in SQL, not just by using standard ANSI syntax.

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