内联注释 sql注释

A comment in any text which is ignored by the compiler and is not executed. It is used to convey some information to the user and used for documentation only, to describe the command's purpose in an application. Comments can be placed anywhere in the statement between any keywords, parameters or punctuation mark in a statement.

用编译器忽略并且不执行的任何文本中的注释 。 它用于向用户传达一些信息，并且仅用于记录文档，以描述应用程序中命令的用途。 注释可以放在语句中任何关键字，参数或标点符号之间的语句中的任何位置。

SQL注释的类型 (Types of SQL Comments)

1. Line Comments

   行注释

2. Block Comments

   阻止评论

1)行注释 (1) Line Comments)

1. Line comments beginning with two dashes (--):

   行注释以两个破折号(-)开头 ：

   Line or Single-Line comments start with two dashes (

   行或单行注释以两个破折号(

   --) and end with carriage returns or line break. Any text between two dashes (--) and end of the line is considered as a comment. These comments can be placed anywhere in the code and everything before dashes (--) will execute like normal MySQL statements and the text after two dashes (--) will not be executed and considered as a comment.

   - )，并以回车或换行结束。 在两个破折号( - )和行尾之间的任何文本均被视为注释。 这些注释可以放在代码中的任何位置，并且破折号( - )之前的所有内容都将像正常MySQL语句一样执行，而两个破折号( - )之后的文本将不被执行并视为注释。

2. Line Comments beginning with a hash sign (#):

   以井号(＃)开头的行注释 ：

   Line or Single-line comments start with a hash sign (

   行或单行注释以井号(

   #) and end with carriage returns or line breaks. Any text between the hash sign (#) and the end of the line is considered as a comment.

   ＃ )并以回车或换行符结束。 井号( ＃ )与行尾之间的所有文本均被视为注释。

Example:

例：

--This illustrates single-line comments.
SELECT *
FROM Student #Student is the table/relational name
WHERE Marks>80;   --This is filter condition

2)块注释 (2) Block Comments)

Block comments or Multi-line comments start with a forward-slash an asterisk (/*) sign and end with asterisk and forward-slash (*/) are considered as comments(multi-line). These comments can be placed anywhere, in, before or after big chunks of code. These comments can extend to more than 1 line.

块注释或多行注释以正斜杠星号( / * )符号开头，以星号和正斜杠( * / )结尾，被视为注释(多行)。 这些注释可以放在大块代码之前，之后的任何位置。 这些注释可以扩展到多于1行。

Example:

例：

/* This is an example of block or multi-line comments
Students table is used to retrieve data on
the basis of filtering condition*/
SELECT *
FROM Student
WHERE marks>80;

Note: There is no limit for comment (in case of block comments). Comments can be nested.

注意：注释没有限制(如果是块注释)。 注释可以嵌套。

翻译自: https://www.includehelp.com/sql/comments.aspx

内联注释 sql注释