Storing data in MySQL - mysql

I want to store some values like "st paul's school" in mysql database. However due to the special symbol ' I am unable to store such values in mysql. I tried varchar datatype but it doesn't work. Please suggest a suitable method or datatype to store ' in mysql.

Add two single quotes like this '' or escape it like this \'

If you are doing it directly on MySQL Server, double the single quote and it will work. Example
INSERT INTO tableName VALUES ('St. Paul''s School')
But on front-end, use PreparedStatements for this.
If you are using PHP, use PDO or MySQLI extension on this to avoid SQL Injection. Please see thearticle below,
How to prevent SQL injection in PHP?

If u have variable with this apostrof use htmlentities
$your_var = "St. Paul's School";
$your_var = htmlentities($your_var);
INSERT INTO tableName VALUES ('$your_var')
If u have just string u can do double quotes like that
INSERT INTO tableName VALUES ("St. Paul's School")

Just replace the quote sign with it's entity.
If you are using php
<?php
$str = "st paul's school";
$str = str_replace("\'","´",$str);
$str = str_replace("\"",""",$str);
?>
You can also use
$str= htmlentities($str,ENT_QUOTES, 'UTF-8');

You can use mysqli_real_escape_string($text) to escape those ' in the text you are inserting to the database.

Related

Getting error when inserting text value in MYSQL [duplicate]

The MySQL documentation says that it should be \'. However, both scite and mysql shows that '' works. I saw that and it works. What should I do?
The MySQL documentation you cite actually says a little bit more than you mention. It also says,
A “'” inside a string quoted with “'” may be written as “''”.
(Also, you linked to the MySQL 5.0 version of Table 8.1. Special Character Escape Sequences, and the current version is 5.6 — but the current Table 8.1. Special Character Escape Sequences looks pretty similar.)
I think the Postgres note on the backslash_quote (string) parameter is informative:
This controls whether a quote mark can be represented by \' in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it ('') but PostgreSQL has historically also accepted \'. However, use of \' creates security risks...
That says to me that using a doubled single-quote character is a better overall and long-term choice than using a backslash to escape the single-quote.
Now if you also want to add choice of language, choice of SQL database and its non-standard quirks, and choice of query framework to the equation, then you might end up with a different choice. You don't give much information about your constraints.
Standard SQL uses doubled-up quotes; MySQL has to accept that to be reasonably compliant.
'He said, "Don''t!"'
What I believe user2087510 meant was:
name = 'something'
name = name.replace("'", "\\'")
I have also used this with success.
There are three ways I am aware of. The first not being the prettiest and the second being the common way in most programming languages:
Use another single quote: 'I mustn''t sin!'
Use the escape character \ before the single quote': 'I mustn\'t sin!'
Use double quotes to enclose string instead of single quotes: "I mustn't sin!"
just write '' in place of ' i mean two times '
Here's an example:
SELECT * FROM pubs WHERE name LIKE "%John's%"
Just use double quotes to enclose the single quote.
If you insist in using single quotes (and the need to escape the character):
SELECT * FROM pubs WHERE name LIKE '%John\'s%'
Possibly off-topic, but maybe you came here looking for a way to sanitise text input from an HTML form, so that when a user inputs the apostrophe character, it doesn't throw an error when you try to write the text to an SQL-based table in a DB. There are a couple of ways to do this, and you might want to read about SQL injection too.
Here's an example of using prepared statements and bound parameters in PHP:
$input_str = "Here's a string with some apostrophes (')";
// sanitise it before writing to the DB (assumes PDO)
$sql = "INSERT INTO `table` (`note`) VALUES (:note)";
try {
$stmt = $dbh->prepare($sql);
$stmt->bindParam(':note', $input_str, PDO::PARAM_STR);
$stmt->execute();
} catch (PDOException $e) {
return $dbh->errorInfo();
}
return "success";
In the special case where you may want to store your apostrophes using their HTML entity references, PHP has the htmlspecialchars() function which will convert them to '. As the comments indicate, this should not be used as a substitute for proper sanitisation, as per the example given.
Replace the string
value = value.replace(/'/g, "\\'");
where value is your string which is going to store in your Database.
Further,
NPM package for this, you can have look into it
https://www.npmjs.com/package/mysql-apostrophe
I think if you have any data point with apostrophe you can add one apostrophe before the apostrophe
eg. 'This is John's place'
Here MYSQL assumes two sentence 'This is John' 's place'
You can put 'This is John''s place'. I think it should work that way.
In PHP I like using mysqli_real_escape_string() which escapes special characters in a string for use in an SQL statement.
see https://www.php.net/manual/en/mysqli.real-escape-string.php

DECODE Function in SQL

I am trying to insert the following query and I get syntax errors. Can you please help me with the below query:
INSERT INTO ABCTABLE (COLUMN1) values ('DECODE(MDSE_CD,NULL,'0000000000000000',LPAD(TO_NUMBER(MDSE_CD,'16',' '))');
Since you haven't really said anything other than "this query doesn't work, fix it", I have to take a stab in the dark what you want. From the query you have, I'm therefore guessing you want the value of the column to be DECODE(MDSE_CD,NULL,'0000000000000000',LPAD(TO_NUMBER(MDSE_CD,'16',' '))
In which case, you have to escape the single quotes within your string literal. Do this by doubling up the quotes:
INSERT INTO ABCTABLE (COLUMN1)
VALUES ('DECODE(MDSE_CD,NULL,''0000000000000000'',LPAD(TO_NUMBER(MDSE_CD,''16'','' ''))')
Try properly escaping the inner single quotes
INSERT INTO ABCTABLE (COLUMN1)
VALUES ('**DECODE**(MDSE_CD,NULL,''0000000000000000'',**LPAD**(TO_NUMBER(MDSE_CD,''16'','' ''))');
The problem is the use of quote marks. If we tried to break up your query it would look like this:
INSERT INTO ABCTABLE
(COLUMN1)
values
(
'DECODE(MDSE_CD,NULL,'
0000000000000000
',LPAD(TO_NUMBER(MDSE_CD,'
16
','
'))'
);
...which clearly makes no sense.
You might want to think about how to escape a quote mark inside a string.
Sql Server:
DECOD function in Sql Server can be replaced with CASE construct
LPAD function in Sql Server has not a direct correspondence but you can pad your string using string manage function REPLACE (replicate a character a number of specified times)
My Sql:
DECOD function in MySql can be replaced with CASE construct
LPAD function in MySql is existent
What do you want to store... a string literal 'DECODE(MDSE...))', or did you want to call a function to derive a value?
To store a string literal containing single quotes, you need to "escape" each single quote within the string with an extra single quote, e.g.
O'Hare Int'l ==> 'O''Hare Int''l'
The DECODE function is Oracle specific. That expression will need to be rewritten using different functions in both MySQL and SQL Server.

How to prevent single quotes when using $this->db->escape in codeigniter

I have insert to columns with single quotes. As $this->db->query already takes care of all the special character. But my problem is i to insert data like ganesh's when the insertion takes place, only ganesh is inserted; data after the single quotes are missing. So i started using $this->db->escape but this adds single quotes to my data which is not required how to prevent this
my code
$sql="insert into tablename (list_name,list_address) values(?,?)"
$res=this->db-query($sql,array($name,$add));
MY mistake was in front end. Not back end. I will delete the question.
In cases of complex queries i find it easier to just send raw query like this :
$query = "your query";
$result = $this->db->query($query);
Don't forget to escape variables before inserting them to the query like this :
$var = $this->db->escape($var);
If you want to save the data with the single quote you will need to add slashes to the data before saving it to the database like this:
$sql="insert into tablename (list_name,list_address) values(?,?)";
$res=this->db-query($sql,array(addslashes($name), $add));
then save that into your database, after doing this you will most likely need to use stripslashes() to remove the slashes from the data before you output it to the browser.

How to escape apostrophe (') in MySql?

The MySQL documentation says that it should be \'. However, both scite and mysql shows that '' works. I saw that and it works. What should I do?
The MySQL documentation you cite actually says a little bit more than you mention. It also says,
A “'” inside a string quoted with “'” may be written as “''”.
(Also, you linked to the MySQL 5.0 version of Table 8.1. Special Character Escape Sequences, and the current version is 5.6 — but the current Table 8.1. Special Character Escape Sequences looks pretty similar.)
I think the Postgres note on the backslash_quote (string) parameter is informative:
This controls whether a quote mark can be represented by \' in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it ('') but PostgreSQL has historically also accepted \'. However, use of \' creates security risks...
That says to me that using a doubled single-quote character is a better overall and long-term choice than using a backslash to escape the single-quote.
Now if you also want to add choice of language, choice of SQL database and its non-standard quirks, and choice of query framework to the equation, then you might end up with a different choice. You don't give much information about your constraints.
Standard SQL uses doubled-up quotes; MySQL has to accept that to be reasonably compliant.
'He said, "Don''t!"'
What I believe user2087510 meant was:
name = 'something'
name = name.replace("'", "\\'")
I have also used this with success.
There are three ways I am aware of. The first not being the prettiest and the second being the common way in most programming languages:
Use another single quote: 'I mustn''t sin!'
Use the escape character \ before the single quote': 'I mustn\'t sin!'
Use double quotes to enclose string instead of single quotes: "I mustn't sin!"
just write '' in place of ' i mean two times '
Here's an example:
SELECT * FROM pubs WHERE name LIKE "%John's%"
Just use double quotes to enclose the single quote.
If you insist in using single quotes (and the need to escape the character):
SELECT * FROM pubs WHERE name LIKE '%John\'s%'
Possibly off-topic, but maybe you came here looking for a way to sanitise text input from an HTML form, so that when a user inputs the apostrophe character, it doesn't throw an error when you try to write the text to an SQL-based table in a DB. There are a couple of ways to do this, and you might want to read about SQL injection too.
Here's an example of using prepared statements and bound parameters in PHP:
$input_str = "Here's a string with some apostrophes (')";
// sanitise it before writing to the DB (assumes PDO)
$sql = "INSERT INTO `table` (`note`) VALUES (:note)";
try {
$stmt = $dbh->prepare($sql);
$stmt->bindParam(':note', $input_str, PDO::PARAM_STR);
$stmt->execute();
} catch (PDOException $e) {
return $dbh->errorInfo();
}
return "success";
In the special case where you may want to store your apostrophes using their HTML entity references, PHP has the htmlspecialchars() function which will convert them to '. As the comments indicate, this should not be used as a substitute for proper sanitisation, as per the example given.
Replace the string
value = value.replace(/'/g, "\\'");
where value is your string which is going to store in your Database.
Further,
NPM package for this, you can have look into it
https://www.npmjs.com/package/mysql-apostrophe
I think if you have any data point with apostrophe you can add one apostrophe before the apostrophe
eg. 'This is John's place'
Here MYSQL assumes two sentence 'This is John' 's place'
You can put 'This is John''s place'. I think it should work that way.
In PHP I like using mysqli_real_escape_string() which escapes special characters in a string for use in an SQL statement.
see https://www.php.net/manual/en/mysqli.real-escape-string.php

MySQL's different quote marks

I am a bit new to MySQL and just wanted to know what is the difference between:
` ' "
when I'm using them in a query.
With ` you write mysql variable names.
With ' you write mysql variable values
For example
SELECT * FROM `test` WHERE `x` = '1'
I would add that the way double quotes are interpreted depend of wether or not your MySQL server has ANSI quotes turned on or off.
In the former you cannot use double quotes as a string delimiter.
SELECT name FROM user WHERE last_name = "norris" ;
will return you a punch in your teeth.
``quotes you dont need to escape where as string quotes you do ''single or ""double
http://dev.mysql.com/doc/refman/5.1/en/string-literals.html
http://dev.mysql.com/doc/refman/5.1/en/identifiers.html
use ` (backquotes) for column name
use ' or " for values
Don't use backticks with column values. use either single or double quotes otherwise mysql considered that value as a column name.