I'm looking around to encode/cast/convert a string into numbers within a query. Like ASCII() but it only returns the left-most character to its relative code. Is there any function or method available on this topic? -which is actually decode-able
JUST For example:
METHOD("test-string") # Outputs: 25478596325417
This will work for strings up to 8 characters long.
To encode:
SELECT CONV(HEX(string), 16, 10);
To decode:
SELECT UNHEX(CONV(number, 10, 16));
MySQL supports integers up to 64 bit long, and this method uses 8 bits per character. Therefore using this method you can store up to 64 / 8 = 8 characters in an integer.
If hexadecimal is good enough for your application, then then function hex() does what you want. For instance, you can try:
select hex('abc'), hex('abcd')
This will work on arbitrary strings. If this doesn't quite work, then perhaps there is a way to convert the hex representation to something appropriate.
By the way, unhex() will return the original string.
You could use
COMPRESS('ABC)
To get a binary string that is not the string. It can compress an arbitrary size. But it is not clear what you are going to do with the number -- or how you need to store it.
Try this one.
SELECT CAST(HEX(your_string) AS DECIMAL);
I admit, I didn't test it, but it should work.
EDIT:
Some other databases (e.g. Oracle, DB2, PostgreSQL) have the function TRANSLATE() for it. Unfortunately MySQL does not support it. And as far as I know no replacement for this function in MySQL exists currently. So using nested REPLACE() is probably the only option currently.
Related
Yet another fun and unexplained issue with MySQL. Code works perfectly fine with all other shorter strings (and has been for months), but when I try to following code on a String that's 8863 in length (designed to simply remove a comma as the last character), it just does nothing. No error or anything. Length is 8863 both before and after the execution (and note the RIGHT check works fine so the LEFT executes, it just fails to remove the last comma). As mentioned, ONLY happens with a very long string.
Anyone know what crazy limitations in MySQL I might be dealing with?
DECLARE var_sql_insert_1 text;
IF (RIGHT(var_sql_insert_1, 1) = ',') THEN
SET var_sql_insert_1 = LEFT(var_sql_insert_1, LENGTH(var_sql_insert_1) - 1);
END IF;
So the issue is I was using LENGTH which was returning the length in BYTES vs. CHAR_LENGTH which returns the length in characters. Sadly, with all the other languages I've used, the default LENGTH value was character and they BYTE_LENGTH was specifically designed to be byte. For MySQL it appears the reverse is true. Doesn't make much sense for a system that's mainly used to store and manipulate TEXT rather than byte data...
Since MySQl 8 where introduced function REGEXP_REPLACE you can use next solution:
SET var_sql_insert_1 = REGEXP_REPLACE(var_sql_insert_1, ',$', '');
The pattern ',$' mean last comma before end of line $
Look the example
Unlike PHP, I don't believe mySQL has any preg_replace() feature, only matching via REGEXP. Here are the strings I have in the code:
http://ourcompany.com/theapplestore/...
http://ourcompany.com/anotherstore/...
http://ourcompany.com/yetanotherstore/...
As you can see, there is a constant in there, http://ourcompany.com/, but there is also a variable string namely theapplestore, anotherstore, etc. etc.
I want to replace the constant string, plus the variable string(s), and then the trailing slash (/) after the variable string(s), with a single shortcode value, namely {{store url=''}}
EDIT
If it helps, the store codes are always the same length, they are going to be
sch131785
sch185399
sch634019
etc.
i.e., they are all 9 characters long
How would I do this? Thanks.
I thought this might be useful: there is currently NO WAY to do this in mysql. Find using REGEXP, yes; replace, no. That said, there is another post with an extension library mentioned, sagi:
Is there a MySQL equivalent of PHP's preg_replace?
MariaDB-10.0.5 has REGEXP_REPLACE(), REGEXP_INSTR() and REGEXP_SUBSTR()
You can use following regex,
(ourcompany.com\/\w+\/)
Demo
Uses the concept of Group Capture
As we all know, we will use the mysql_query api to send a query to the server, and the query are passed by a string as the parameter. And we will have to formulate the string outside the mysql_query called by some C functions like sprintf.For example,
sprintf(buffer, “insert into table(describe) values(‘%s’)”, strA);
mysql_query(..., buffer);
The ‘describe’ is a VARCHAR(150).
In some special cases, one of our functions will cat several C style string into a long one remaining all the ending ‘\0’ to form a binary, ie in C form catting “abc” and “efg” into “abc\0efg\0”, of course with the length given out to the caller(in this case, it is 8). However, the out binary can NEVER be used in the sprintf above as strA, as the C functions will truncate the string by meeting the first ‘\0’.
Is there anything special we can do to fulfill our needs? We want to insert a binary into a column defined as VARCHAR. We have tried to change all the ‘\0’ into ‘\0’ literally, which seems to work good but time and codes consuming. Is there any alternative easier method?
Thanks in advance.
you should use mysql_real_escape_string() to escape this string.
So lets just say I have a table with just an ID is an int. I have discovered that running:
SELECT *
FROM table
WHERE ID = '32anystring';
Returns the row where id = 32. Clearly 32 != '32anystring'.
This seems very strange. Why does it do this? Can it be turned off? What is the best workaround?
It is common behavior in most programming languages to interpret leading numerals as a number when converting a string to a number.
There are a couple of ways to handle this:
Use prepared statements, and define the placeholder where you are putting the value to be of a numeric type. This will prevent strings from being put in there at all.
Check at a higher layer of the application to validate input and make sure it is numeric.
Use the BINARY keyword in mysql (I'm just guessing that this would work, have never actually tried it as I've always just implemented a proper validation system before running a query) -
SELECT *
FROM table
WHERE BINARY ID = '32anystring';
You need to read this
http://dev.mysql.com/doc/refman/5.1/en/type-conversion.html
When you work on, or compare two different types, one of them will be converted to the other.
MySQL conversion of string->number (you can do '1.23def' * 2 => 2.46) parses as much as possible of the string as long as it is still a valid number. Where the first letter cannot be part of a number, the result becomes 0
I have several rows with strings similar to this: 1,19|11|14,2
The info I want to look at is: 19|11|14 (which is a list of the numbers, 19 11 and 14)
This info should be matched to see if any of the numbers are in the range between 8 and 13
What's the most effective way to accomplish this? I tried using a regexp like: [^0-9]*(8|9|10|11|12|13)[^0-9]*
But this would also match the number 9 which is actually 19.
Other methods for parsing the string is also welcomed, only functions available in MySQL 5.0 can be used.
From what I remember MySQLs Regex support is very simplistic I'm not sure how possible this will actually be. I don't believe it supports word boundaries or look around assertions. How about this...
(^|[^0-9])(8|9|10|11|12|13)([^0-9]|$)