Introduction
SQL is a Structured Query Language, and it is used for storing, retrieving and manipulating data from databases. It helps handle structured data like the data stored in tabular form. This article will discuss some SQL problems, which will clear most doubts from different topics. The difficulty level of the problems will be miscellaneous.
Problems
- In Structured Query Language, which of the following is not a constraint?
a. NOT NULL
b. SELECT
c. PRIMARY KEY
d. CHECK
Ans: B
Explanation: The constraint defines the rule that determines whether or not data may be put in a table. The constraints PRIMARY KEY, NOT NULL, and CHECK provide the criteria for data insertion.
- What does the CREATE command do?
a. You can delete or remove recorded data from a database with this command.
b. This command allows you to insert records or data into the database tables. We have the option of entering records in multiple rows and single rows.
c. This command allows you to build new databases, tables, table views, and other objects.
d. This command can get a single or numerous rows from one or more database tables. This command can also be used with the WHERE clause.
Ans: C
Explanation: You can use the CREATE command to make new databases, tables, table views, and other objects.
- What is the work of the CREATE TABLE statement?
a. A new table is created using this command.
b. This SQL statement can add, remove, or modify columns in a SQL database.
c. This SQL statement modifies or changes the stored data in the SQL database.
d. None of the above
Ans: A
Explanation: The CREATE TABLE SQL command is used to create a new table in SQL.
- How many different sorts of data types have been classified?
a. 3
b. 4
c. 5
d. None of the above
Ans: A
Explanation: There are three sorts of data types- String, Numeric and Date&Time.
- In MySQL Numeric Data Types, what does BOOL mean?
a. This variable specifies a Boolean value. Nonzero values are deemed false, whereas zero values are considered true.
b. This variable specifies a Boolean value. Nonzero values are regarded as true, whereas zero values are deemed false.
c. This variable specifies a Boolean value. Nonzero values are deemed true, and zero values are also considered true.
d. This variable specifies a Boolean value. Nonzero values are regarded as false, and zero values are also considered false.
Ans: A
Explanation: A Boolean value is specified by this variable. Nonzero values are deemed false, whereas zero values are considered true.
- The Modulus Operator in SQL returns the
a. Null
b. Quotient
c. Reminder
d. Zero
Ans: C
Explanation: The Reminder is produced by the SQL Modulus Operator.
- The SQL Division operator divides the ___ side operand by the ___ side operand.
a. Right, Left
b. Right, Right
c. Left, Right
d. Left, Left
Ans: C
Explanation: The SQL Division operator divides the left side operand by the right side operand.
- DDL stands for
a. Definition Data Language
b. Data Definition Language
c. Distinct Data Language
d. None of the Above
Ans: B
Explanation: DDL stands for Data Definition Language.
- Following the completion of a transaction, it must be completed to store all of the transactions' operations. Which command are we addressing here?
a. DELETE
b. COMMIT
c. ROLLBACK
d. SAVE
Ans: B
Explanation: To preserve all of the activities performed in a transaction, the COMMIT command must be used once completed.
- Which SQL command can be used to change the table's name?
a. ALTER
b. RENAME
c. Both a and b
d. None of the above
Ans: C
Explanation: The RENAME and ALTER commands in SQL can be used to modify the table's name.
- What is the difference between the DELETE and TRUNCATE statements?
a. The DELETE statement releases the space held in reserve by the table, but the TRUNCATE command does not.
b. The TRUNCATE command can only delete columns from the table, whereas the DELETE statement can only delete rows.
c. TRUNCATE statement can only delete rows from the table, whereas the DELETE statement can only delete columns.
d. The DELETE statement does not free up the space that the table is holding in reserve; however, the TRUNCATE command does.
Ans: D
Explanation: The DELETE statement does not free up the space that the table is holding in reserve; however, the TRUNCATE command does.
- What is the purpose of the UCASE function?
a. To convert the string's case to numeric characters.
b. To make the string's case lowercase.
c. To make the string uppercase.
d. To make the string's case symbolic characters.
Ans: C
Explanation: To convert the case of a string to uppercase characters, use the UCASE function.
- Which SQL Function is used to change the expression from one data type to another?
a. HAVING
b. CAST
c. CONVERT
d. CHANGE
Ans: B
Explanation: The SQL CAST Function transforms the expression from one data type to another.
- In the CAST function, what is the default length of any data type?
a. 20
b. 30
c. 40
d. 50
Ans: B
Explanation: In the CAST function, the default length of any data type is 30.
- MINUS Operator displays the rows that are
a. Detected in the second query but not in the first, there are no duplications.
b. Detected in the first query but not in the second, there are no duplications.
c. Detected in the first query but not in the second, there are duplications.
d. Detected in the second query but not in the first, and there are duplications.
Ans: B
Explanation: Detected in the first query, absent in the second query. There are no duplications.
Let's discuss some frequently asked questions.
Frequently Asked Questions
What is SQL?
SQL stands for Structured Query Language, and it is used to store, retrieve and manipulate data.
Which syntax is used for single-line comments?
( — ), A double hyphen is used for single-line comments.
This article discussed some problems related to SQL. And then discussed the answers with proper explanation. Learn more about SQL problems, competitive programming & other programming languages and solve them on your own.
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