Introduction to MySQL statement comments

MySQL supports three types of comments:

1. From the '#' character from the end of the line.

2. From the '--' sequence to the end of the line. Please note that the '-- ' (double dash) comment style requires that the second dash be followed by at least one whitespace character (eg space, tab, newline, etc.).

3. From the /* sequence to the following */ sequence. The closing sequence does not have to be on the same line, so this syntax allows comments to span multiple lines.

The following example shows 3 styles of comments:

//How to write comment statements in mysqlmysql> SELECT 1+1; # This comment continues until the end of the linemysql> SELECT 1+1; -- This comment continues until the end of the linemysql> SELECT 1 /* This is a comment in the middle of a line*/ + 1;
mysql> SELECT 1+
/*
This is a multi-line comment form */
1;

The above comment syntax applies to how the mysqld server parses SQL statements. The MySQL client also performs some statement parsing before sending it to the server. (For example, it parses to determine statement boundaries in multi-statement lines).

Summarize

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