String functionsstring comparison functionsIf the length of the result is greater than the maximum value of the Max_allowed_packet system variable, the return value of the string value function is null. See section 7.5.2, "Tuning server parameters."
In PHP, escape and inverse meanings of strings can also be implemented using the addslashes () and stripslashes () functions provided by PHP. In PHP, the escape and inverse meanings of strings can be implemented using the self-owned functions
A string or string (string) is a finite sequence consisting of 0 or more characters. Generally recorded as s= ' a1a2 an ' (n>=0). It is the data type that represents text in the programming language.
A string is usually used as an action object,
In a string, some sequences have special meanings. These sequences start with a backslash ('\').Escape characters. MySQL recognizes the following escape sequence:
\ 0
ASCII 0 (NUL) characters.
\'
Single quotes (''').
A string is usually used as an action object, such as finding a substring in a string, seeking a substring, inserting a substring at a point in a string, and deleting a substring. The necessary and sufficient condition for two strings to be equal is
For more information, see MySQL escape characters.
For more information, see MySQL escape characters.
MySQL Escape Character "\"
Mfc_basic
MySQL recognizes the following escape characters:
\ 0
An ASCII 0 (NUL) character.
\ N
A newline character.
\
Php implements the code for handling input escape characters, and php escape character code. Php implements the code for handling input escape characters. The php escape character code first comes with a function, which is ***
1: String Join function
The code is as follows
Copy Code
CONCAT (STR1,STR2,...)
Returns a string resulting from a connection parameter. If any of the arguments are null, the return value is null. There may be
The escape character. MySQL recognizes the following escape sequencesIn a string, some sequences have special meanings. These sequences begin with a backslash (' \ '), the so-called escape character. MySQL recognizes the following escape
For example, in a data table there is a field called
orderis specifically used for sorting, and my statement may have to be written like this.
$sth = $pdo->prepare (' SELECT * FROM table_name ORDER by order ASC '); $sth->execute ();
But because
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