so employers test candidates on various concepts ranging from basic to advanced-level queries. This blog covers common SQL interview questions and their answers to help you succeed in your next interview.
A query, in SQL, is a command used to request data or update information from a database table or combination of tables. Users can write and execute queries to retrieve, delete or update information in a database. Usually, a query response returns data from different tables within the data...
It is the collection of schemes, tables, queries, reports, views and other objects.Syntax: CREATEDATABASEDatabaseNameExample: CREATEDATABASE Studentor you can Create Database through Design/ Wizard form by right clicking on DATABASE option-New Database....
Sub-queries are often referred to as sub-selects, as they allow a SELECT statement to be executed arbitrarily within the body of another SQL statement. A sub-query is executed by enclosing it in a set of parentheses. Sub-queries are generally used to return a single row as an atomic val...
Eventually, in an outer query, apply aWHEREfilter and aCOUNT()function on the result of the subquery. Solution of SQL Interview Question #3 Solution: SELECT department_name, AVG(salaries.salary) AS avg_salariesFROM employeesJOIN salariesON employees.employee_id = salaries.employee_idGROUP BY dep...
Joins are used in queries to explain how different tables are related. Joins also let you select data from a table depending upon data from another table. Types of joins: INNER JOINs, OUTER JOINs, CROSS JOINs.OUTER JOINs are further classified as LEFT OUTER JOINS, RIGHT OUTER JOINS and FULL...
3 to_char(sysdate,'sssss') "Seconds" 4 from dual; SystemTime Seconds --- --- 11:34:50 41750 Video for Complex sql queries : Register for free and Get Complex SQL Interview Questions PDF : Submit FOR ISSUES CONTACT : compexsql@gmail.com...
What are SQL interview questions for data analyst in 2021? ,SQL interview questions for data analyst, SQL interview queries for data analyst with examples
We can check the current settings and thread allocation using the below queries. –Thread setting select max_workers_count from sys.dm_os_sys_info –Active threads select count(*) from sys.dm_os_threads Default value is 255. Increasing the number of worker threads may actually decrease the ...
they are just used to speed up queries. Effective indexes are one of the best ways to improve performance in a database application. A table scan happens when there is no index available to help a query. In a table scan SQL Server examines every row in the table to satisfy the query ...