If there is no match in the left table, the result will contain null values. SELECT candidates.name, employees.name AS employee FROM candidates LEFT JOIN employees ON candidates.name = employees.name ģ) Right join: Returns all the rows from the right table, and the matching rows from the left table. If there is no match in the right table, the result will contain null values. SELECT candidates.name FROM candidates INNER JOIN employees ON candidates.name = employees.name Ģ) Left join: Returns all the rows from the left table, and the matching rows from the right table. The candidates table contains the names of interview candidates, and the employees table contains the names of the company employees, some of which are the candidates who have been selected and converted into employees.ġ) Inner join: Returns only the rows that match in both tables. I will explain each of them with examples using two sample tables: candidates and employees. There are five types of SQL joins: inner, left, right, full, and cross. SQL joins are used to combine data from multiple tables based on a common column. If you have any questions or feedback, please leave a comment below. I hope this post is helpful and informative. They are responsible for transferring electronic mail and computer files between clients and servers. SMTP (Simple Mail Transfer Protocol) and FTP (File Transfer Protocol) are two of the oldest and most widely used application-layer protocols in the internet protocol suite. UDP is suitable for applications that require speed and efficiency over reliability and order, such as voice and video streaming, online gaming, and DNS (Domain Name System). UDP does not establish a connection between the sender and the receiver, and does not use any mechanisms to recover from packet loss, duplication, or corruption. UDP is an unreliable and unordered protocol that does not guarantee that every packet sent will be received by the destination, nor that the packets will arrive in the same order as they were sent. TCP achieves this by establishing a connection between the sender and the receiver, and by using acknowledgments, retransmissions, and checksums to handle packet loss, duplication, and corruption. TCP is a reliable and ordered protocol that guarantees that every packet sent will be received by the destination, and that the packets will arrive in the same order as they were sent. They are responsible for sending packets (units of data) across the internet and ensuring the successful delivery of data and messages over networks. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are two of the most widely used protocols in the internet protocol suite. Unlike HTTP, which is based on a request-response model, WebSocket allows clients and servers to exchange data in real-time without waiting for each other. WebSocket provides full-duplex (two-way) communications over a single TCP connection. HTTP/3 runs on QUIC (Quick UDP Internet Connections), a new transport protocol that uses UDP (User Datagram Protocol) instead of TCP (Transmission Control Protocol). HTTP/3 is the next version of HTTP, which improves the performance and reliability of web applications. HTTPS (HyperText Transfer Protocol Secure) adds encryption to HTTP, making the data transfer more secure and private. HTTP is stateless, meaning that each request is independent and does not remember any previous interactions. HTTP (HyperText Transfer Protocol) allows clients (such as browsers) to request and receive resources (such as HTML documents) from servers. In this post, I will briefly explain some of the most common and important protocols. Web protocols are the rules that enable data transfer and communication over the internet.
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