How to use the mysql select query statement?

2 years ago
William Carter
2 minutes

The SELECT statement in MySQL is used to retrieve data from a database.

The general syntax of a SELECT statement is as follows:

SELECT 列名或表达式
FROM 表名
[WHERE 条件]
[ORDER BY 列名 [ASC | DESC]]

The column names or expressions are used to specify the data columns to retrieve, and * can be used to retrieve all columns. The table name is used to specify the table from which to retrieve data. The WHERE clause is used to specify the conditions for retrieving data. The ORDER BY clause is used to specify the sorting order of the retrieval results, with the default being in ascending order.

Here are some examples of SELECT statements:

  1. Retrieve data from all columns.
SELECT * FROM 表名;
  1. Retrieve data from specified columns.
SELECT 列名1, 列名2 FROM 表名;
  1. Retrieve data that meets the criteria.
SELECT * FROM 表名 WHERE 条件;
  1. Retrieve and sort by specified column.
SELECT * FROM 表名 ORDER BY 列名 ASC;  -- 升序排序
SELECT * FROM 表名 ORDER BY 列名 DESC; -- 降序排序
  1. Search specific column and sort by specified column.
SELECT 列名1, 列名2 FROM 表名 ORDER BY 列名1 ASC, 列名2 DESC;

The above are just some common usages of the SELECT statement, there are more advanced techniques like using aggregate functions and limiting the number of results with LIMIT. In practice, the SELECT statement can be used flexibly according to specific needs.

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