Posts

Showing posts from April, 2024

Joins in SQL

Image
JOINS IN SQL  Joins are used to combine row from two or more tables, based on a related column between them.   Types of Joins in MySQL  are -: Inner Joins left Joins Right Joins Cross Joins Now we will  explain in details with examples Inner Joins -  The SQL  ' INNER JOIN'  statement joins two tables based on a common column and selects rows that have matching values in these columns. INNER JOIN , which tells the SQL engine the name of the table you wish to join in your query, and that you wish to use an inner join. ON , which tells the SQL engine what columns to use to join the two tables.        Joins are usually used in a query after the  FROM  clause.  Left Joins- Returns all record from the Left table, and the matching records from the Right table.   While the left join includes all rows in the table  before  the JOIN  clause. Right Joins-   Returns all record from the Right table, and ...

Most Asked SQL Queries on Interviews

Image
    Top 10 Frequently SQL  Queries Asked for Interviews  SQL (Structured Query Language) is a crucial skill for anyone working with data and is often a topic in job interviews for data-focused roles. When preparing for interviews for positions like data analyst, data engineer, or database administrator, anticipate encountering questions about SQL. What are the uses of SQL? SQL's significance in data-centric positions cannot be overstated. As a domain-specific language tailored for managing and querying relational databases, SQL is indispensable. It is essential for tasks like data retrieval, result filtering, information aggregation, or merging data from various sources. It makes SQL a fundamental instrument for data experts. Here we will explore the top 10 frequently asked SQL queries with explanation. 1. Retrieving data from a table The ' SELECT ' statement is the foundation of SQL. It allows you to retrieve data from a specified table.      --...