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In this article, we will introduce MySQL comments. We will also understand what type of comments should be used and where. Comments are written to describe the code and make it easier to understand. We also use comments to ignore a part of...

Today's tutorial is an introduction to MySQL composite keys. This lesson also discusses the use of the CREATE and ALTER statements to create composite primary and foreign keys. Introduction to MySQL composite keys A composite key is a type...

There are many articles about finding the last inserted ID of a table in MySQL. However, it is hard to find any tutorials about finding the last inserted ID using two tables. In this article, we will try to solve this special case, and of c...

Today, we will learn 等待表元数据锁定 . This article focuses on the causes of metadata lock waits and provides solutions. What are locks in MySQL? A lock is a mechanism associated with a table to restrict unauthorized access to the...

JSONB is a decomposed binary format for storing JSON data. If you follow Google Trends or do some research, you'll see that JSON is becoming increasingly popular in the development world. Nowadays, NoSQL can store JSON data by default. It i...

This article will discuss how to find the disk size of a PostgreSQL table and its indexes. Find the disk size of PostgreSQL tables and databases using PSQL You can use \l+ to view the database size and use to \d+ show table size. But before...

When developing an application, developers must understand the different ways they can use to interact with the database. This knowledge will help improve development efficiency because they will know the best way to solve a specific proble...

When we try to connect to the database, Postgres uses SSL to verify the security of the connection. It is disabled by default in HTTP, but in HTTPS, we need the SSL mode of the connection to perform any operation in the Postgres database. I...

When we develop applications, we end up hosting them with the desired cloud providers under specific monthly or annual subscriptions. Depending on your plan, these subscriptions provide us with different services like data stored in databas...

Unlike SQL Server, PostgreSQL does not have a built-in DATEDIFF function to calculate the difference between dates. However, you can use expressions that include other functions provided by PostgreSQL to obtain the difference between dates....

In this tutorial, we will learn how to insert data from a database hosted on a remote server into a database in our local computer. We will use the remote service provider Heroku PostgreSQL, which offers a free plan for testing purposes. In...

PostgreSQL provides many functions and operators for built-in data types. This tutorial will give an example of extracting the date from a timestamp in PostgreSQL or Postgres. CAST Extracting the date from a timestamp using the operator in...

In this article, we will learn how DATEFIELD to find the day of the week from a given in the table in PostgreSQL. We will also learn about different operations that you can use to manipulate and work with DATEFIELD the data in . We use EXTR...

Before we begin, let's define what a timestamp is in SQL. From the PostgreSQL documentation under the DATE/TIME heading, a timestamp is a data type that stores a date and time in the following format. YYYY-MM-DD hh:mm:ss (DATE | TIME) The s...

with Statements are used to create temporary tables, which means that these tables are not persisted in the database and exist only in memory until the query is completed. The statement was introduced with to break down complex queries into...