Thursday, October 9, 2008

คอมเม้น sql statement ใน MySQL

How to comment Comment Syntax MySQL.

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MySQL Server supports three comment styles:

- From a “#” character to the end of the line.

- From a “-- ” sequence to the end of the line. In MySQL, the “-- ” (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on). This syntax differs slightly from standard SQL comment syntax, as discussed in Section 1.8.5.6, “'--' as the Start of a Comment”.

- From a /* sequence to the following */ sequence, as in the C programming language. This syntax allows a comment to extend over multiple lines because the beginning and closing sequences need not be on the same line.

Sample

mysql> SELECT 1+1; # This comment continues to the end of line
mysql> SELECT 1+1; -- This comment continues to the end of line
mysql> SELECT 1 /* this is an in-line comment */ + 1;
mysql> SELECT 1+
/*
this is a
multiple-line comment
*/
1;

Result: #, /**/ , ' (for SQLServer)

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