Problem Description & Analysis: The first two columns of a certain database table have duplicate values, such as the 2nd-3rd records and the 1st record being duplicated below. Task: Now we need to change all duplicate values to null. In other words,...
If you've been searching for a simple yet effective way to learn SQL, you're in the right place. This SQL Tutorial (2025 Edition) from Tpoint Tech is crafted to help beginners and intermediate learners grasp SQL concepts quickly—using real-world exam...
Problem Description & Analysis: A certain database table records the planned inbound quantity and total inventory after inbound on specific dates, such as the planned inbound quantity of 0.6 on February 26th, resulting in a total inventory of 3. Tas...
Here i have created a list of basic commands using which you can operate or work with different databases like sqlite3 or PostgreSQL, MySQL etc. SQLite3: Create a database: sqlite3 database_name.db Show all tables: .tables View all table schema: ...
Problem Description & Analysis: There are two tables in a certain database. The original inventory table data_add stores multiple batches of inventory for multiple items. Each batch of inventory has a starting number START_NUM and an ending number EN...
Today was a super fun and insightful day in my MySQL journey 😄. Under the amazing guidance of Shafiq Sir, I revised some core MySQL concepts with hands-on experience — and trust me, learning this way feels different! No just theory, only practical m...
Introduction Handling NULL values is a common challenge when working with databases. Whether you're running complex reports, cleaning up data, or ensuring your results are readable and reliable, NULL values can disrupt your SQL logic. That’s where th...
Problem Description & Analysis: A certain database has a ticket table and a work hour table. The ticket table stores the relationship between each ticket and its parent ticket, forming a self-association structure: The work hour table stores multipl...
Problem Description & Analysis: The Snowflake database has a multi-layered JSON string: { "enterprise": "xx", "genericTrap": "1", "pduBerEncoded": "xxx", "pduRawBytes": "xxxx", "peerAddress": "xx", "peerPort": "xx", "securityName": "xxx...
Problem description & analysis: The Time field of a certain database table is time, and the time interval is sometimes greater than 1 minute. Task: Now we need to divide the data into windows every minute, fill in the missing windows, and calculate ...
