mysql - 是否可以获得所有 MySQL 系统函数的列表？

Question

我看起来像：

SHOW FUNCTION STATUS

获取当前服务器版本的所有可用系统功能的列表。可以直接从 MySQL 引擎获取像这里这样的表吗？

谢谢！

Answer 1

如果您已经安装了帮助表（大多数二进制发行版都安装了；fill_help_tables.sql如果没有安装，则会调用一个脚本），您可以输入：

mysql> HELP FUNCTIONS
You asked for help about help category: "Functions"
For more information, type 'help <item>', where <item> is one of the following
topics:
       PROCEDURE ANALYSE
categories:
   Bit Functions
   Comparison operators
   Control flow functions
   Date and Time Functions
   Encryption Functions
   Information Functions
   Logical operators
   Miscellaneous Functions
   Numeric Functions
   String Functions

...然后是这样的：

mysql> HELP String Functions
You asked for help about help category: "String Functions"
For more information, type 'help <item>', where <item> is one of the following
topics:
  ASCII
  BIN
  BINARY OPERATOR
  BIT_LENGTH
  CAST
  CHAR FUNCTION
...

...在最后做类似的事情之前：

mysql> HELP bin
Name: 'BIN'
Description:
Syntax:
BIN(N)

Returns a string representation of the binary value of N, where N is a
....

如何生成自己的列表！

以下查询（在mysql数据库上）在一个列表中提供了所有函数及其类别：

SELECT help_category.name, help_topic.name 
FROM help_topic JOIN help_category 
    ON help_category.help_category_id = help_topic.help_category_id 
WHERE help_category.help_category_id IN (
    SELECT help_category_id FROM help_category 
    WHERE parent_category_id=37
) ORDER BY 1;

如果你想要每个的文本描述，只需description在子句中添加一个列SELECT，虽然它很长，所以你可能想要使用\G而不是;