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SQL Basics

1/25 With SQL, how do you select all the columns from a table named "Products"?
- SELECT [all] FROM Products
- SELECT All Products
- SELECT *.Products
- SELECT * FROM Products
2/25 What SQL keyword is applied for sorting the result-set?
- SORT BY
- ORDER
- ORDER BY
- SORT
3/25 Which SQL statement is applied for returning only different values?
- SELECT UNIQUE
- SELECT INDENTITY
- SELECT DIFFERENT
- SELECT DISTINCT
4/25 Which of the following is true about CASE SQL statement?
- A way to establish an IF-THEN-ELSE in SQL.
- A way to establish a loop in SQL.
- A way to establish a data definition in SQL.
- All of the above.
5/25 Which of the following statements is true about embedded SQL?
- Hard-coded SQL statements in a program language such as Java.
- The process of making an application capable of generating specific SQL code on the fly.
- Hard-coded SQL statements in a procedure.
- Hard-coded SQL statements in a trigger.
- Embedded SQL is applied for returning data that will be used in the main query as a condition.
6/25 What does AVG SQL return?
- The maximum value from a column.
- The sum of values in a column.
- The average of the values in a group.
7/25 How else can the table columns be called?
- Attributes
- Fields
- Records
8/25 Can the SELECT clause list have a computed value like in the example below? SELECT CustomerName, UnitPrice * NumberofUnits FROM Sale.
- No
- Yes
9/25 How do you use a subquery to find names of customers who have placed orders in an 'Orders' table?
- SELECT Name FROM Customers WHERE CustomerID IN (SELECT CustomerID FROM Orders)
- SELECT CustomerID FROM Orders WHERE Name IN (SELECT Name FROM Customers)
- SELECT Name FROM Customers WHERE EXISTS (SELECT CustomerID FROM Orders)
- SELECT Name FROM Customers JOIN Orders ON Customers.CustomerID = Orders.CustomerID
10/25 Which SQL data type is used to store fixed-length character strings?
- VARCHAR
- TEXT
- CHAR
- STRING
11/25 What is the purpose of constraints in SQL?
- To limit the type of data that can be stored in a column.
- To join tables together based on a condition.
- To sort the data in ascending or descending order.
- To group data based on column values.
12/25 What does the SQL statement 'BEGIN TRANSACTION' do?
- Starts a new SQL transaction.
- Creates a new table called TRANSACTION.
- Begins a new subquery.
- Starts a new index creation process.
13/25 How can you lock a table 'Employees' for read and write operations to maintain data integrity?
- LOCK TABLE Employees READ, WRITE
- SET LOCK ON Employees
- EMPLOYEES LOCK SET READ, WRITE
- TABLE Employees SET LOCK
14/25 How do you update the 'Salary' column in the 'Employees' table for an employee with 'EmployeeID' 123 to 50000?
- UPDATE Employees SET Salary = 50000 WHERE EmployeeID = 123
- CHANGE Employees SET Salary = 50000 WHERE EmployeeID = 123
- MODIFY Employees SET Salary = 50000 WHERE EmployeeID = 123
- EDIT Employees SET Salary = 50000 FOR EmployeeID = 123
15/25 Which SQL statement is used to set a default value for a column?
- SET DEFAULT
- ALTER TABLE ... SET DEFAULT
- MODIFY COLUMN ... DEFAULT
- UPDATE COLUMN ... SET DEFAULT
16/25 What is the result of executing a SQL statement that includes a WHERE clause with a non-existent value?
- An error message.
- All records from the table.
- No records (an empty result set).
- The first record in the table.
17/25 What does the SQL clause 'LIMIT 10' do when added to a SELECT statement?
- Limits the result to the first 10 rows.
- Selects only the 10th row.
- Limits each column to 10 characters.
- Throws an error as 'LIMIT' is not a valid SQL clause.
18/25 What is the result of the following query: SELECT COUNT(DISTINCT EmployeeName) FROM Employees?
- The total number of rows in the Employees table
- The number of unique employee names in the Employees table
- A syntax error
- The first unique employee name in the Employees table
19/25 How do you delete a table named 'TemporaryData' only if it exists in the database?
- DROP TABLE IF EXISTS TemporaryData
- DELETE TABLE TemporaryData IF EXISTS
- REMOVE TABLE TemporaryData WHEN EXISTS
- DROP TABLE TemporaryData ONLY IF EXISTS
20/25 Which SQL statement is used to change the data type of a column in an existing table?
- ALTER TABLE table_name MODIFY column_name new_data_type
- UPDATE TABLE table_name SET column_name TYPE new_data_type
- CHANGE TABLE table_name column_name new_data_type
- MODIFY TABLE table_name column_name SET TYPE new_data_type
21/25 What is the primary purpose of the SQL 'INNER JOIN' clause?
- To combine rows from two or more tables based on a related column between them
- To retrieve rows that exist in one table but not in another
- To select all rows from both tables regardless of the match between columns
- To update records in one table based on values in another table
22/25 In SQL, which command is used to change the structure of a table such as adding a column or changing a column type?
- MODIFY TABLE
- CHANGE TABLE
- ALTER TABLE
- UPDATE TABLE
23/25 How can you retrieve unique values from the column 'EmployeeName' of the 'Employees' table?
- SELECT DISTINCT EmployeeName FROM Employees
- SELECT UNIQUE EmployeeName FROM Employees
- GET ALL UNIQUE EmployeeName FROM Employees
- SELECT EmployeeName FROM Employees DISTINCT
24/25 Which SQL clause is used to sort the result set in ascending or descending order?
- SORT BY
- ORDER BY
- ARRANGE BY
- SEQUENCE BY
25/25 In SQL, which command is used to add a new column to an existing table?
- ADD COLUMN column_name TO table_name
- INSERT COLUMN column_name INTO table_name
- ALTER TABLE table_name ADD column_name column_type
- UPDATE TABLE table_name SET ADD column_name column_type
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