Common SQL Interview Question

1). What is table?

A table is the basic unit of data storage in an database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.

2).What are the various types of queries?

The types of queries are : Normal Queries, Sub Queries, Co-related queries, Nested queries, Compound queries.

3). What is SELECT statement?

The most commonly used SQL command is SELECT statement. The SQL SELECT statement is used to query or retrieve data from a table in the database.

4).What is SQL Alias?

SQL Aliases are defined for columns and tables. Basically aliases is created to make the column selected more readable.

5).What is SQL WHERE Clause?

The WHERE Clause is used when you want to retrieve specific information from a table excluding other irrelevant data.

6).What is SQL Operators?

There are two type of Operators, namely Comparison Operators and Logical Operators. These operators are used mainly in the WHERE clause, HAVING clause to filter the data to be selected.

7). What is SQL Logical Operators?

There are three Logical Operators namely, AND, OR, and NOT. These operators compare two conditions at a time to determine whether a row can be selected for the output. When retrieving data using a SELECT statement, you can use logical operators in the WHERE clause, which allows you to combine more than one condition.

8).What is ORDER By Keyword?

The ORDER BY keyword is used to sort the result-set by a specified column. The ORDER BY keyword sort the records in ascending order by default. If you want to sort the records in a descending order, you can use the DESC keyword.

9). What is INSERT statement?

The INSERT INTO statement is used to insert a new row in a table.

10).What is UPDATE Statement?

The UPDATE statement is used to update existing records in a table.

11).What is DELETE Statement?

The DELETE statement is used to delete rows in a table.