Learning MySQL from Scratch: Mastering Data Extraction with Query Statements

This article introduces the basics of MySQL. First, it explains that MySQL is an open-source relational database used for storing structured data (such as users, orders, etc.). Before use, it needs to be installed and run, and then connected through graphical tools or command lines. Data is stored in the form of "tables", which are composed of "fields" (e.g., id, name). For example, a student table includes fields like student ID and name. Core query operations include: basic queries (`SELECT * FROM table_name` to retrieve all columns, `SELECT column_name` to specify columns, `AS` to set aliases); conditional queries (`WHERE` combined with comparison operators, logical operators, and `LIKE` for fuzzy matching to filter data); sorting (`ORDER BY`, default ascending `ASC`, descending with `DESC`); limiting results (`LIMIT` to control the number of returned rows); and deduplication (`DISTINCT` to exclude duplicates). It also provides comprehensive examples and practice suggestions, emphasizing familiarizing oneself with query logic through table creation testing and combined conditions. The core of MySQL queries: clarify requirements → select table → specify columns → add conditions → sort/limit. With more practice, one can master query operations proficiently.