I have a table "locales" with a column named "name". The records in name always begin with a number of characters folowed by an underscore (ie "foo_", "bar_"...). The record can have more then one underscore and the pattern before the underscore may be repeated (ie "foo_bar_", "foo_foo_").
How, with a simple query, can I get rid of everything before the first underscore including the first underscore itself?
I know how to do this in PHP, but I cannot understand how to do it in MySQL.
SELECT LOCATE('_', 'foo_bar_') ... will give you the location of the first underscore and SUBSTR('foo_bar_', LOCATE('_', 'foo_bar_')) will give you the substring starting from the first underscore. If you want to get rid of that one, too, increment the locate-value by one.
If you now want to replace the values in the tables itself, you can do this with an update-statement like UPDATE table SET column = SUBSTR(column, LOCATE('_', column)).
select substring('foo_bar_text' from locate('_','foo_bar_text'))
MySQL REGEXs can only match data, they can't do replacements. You'd need to do the replacing client-side in your PHP script, or use standard string operations in MySQL to do the changes.
UPDATE sometable SET somefield=RIGHT(LENGTH(somefield) - LOCATE('_', somefield));
Probably got some off-by-one errors in there, but that's the basic way of going about it.
Related
So I'm trying to find what "special characters" have been used in my customer names. I'm going through updating this query to find them all one-by-one, but it's still showing all customers with a - despite me trying to exlude that in the query.
Here's the query I'm using:
SELECT * FROM customer WHERE name REGEXP "[^\da-zA-Z\ \.\&\-\(\)\,]+";
This customer (and many others with a dash) are still showing in the query results:
Test-able Software Ltd
What am I missing? Based on that regexp, shouldn't that one be excluded from the query results?
Testing it on https://regex101.com/r/AMOwaj/1 shows there is no match.
Edit - So I want to FIND any which have characters other than the ones in the regex character set. Not exclude any which do have these characters.
Your code checks if the string contains any character that does not belong to the character class, while you want to ensure that none does belong to it.
You can use ^ and $ to check the while string at once:
SELECT * FROM customer WHERE name REGEXP '^[^\da-zA-Z .&\-(),]+$';
This would probably be simpler expressed with NOT, and without negating the character class:
SELECT * FROM customer WHERE name NOT REGEXP '[\da-zA-Z .&\-(),]';
Note that you don't need to escape all the characters within the character class, except probably for -.
Use [0-9] or [[:digit:]] to match digits irrespective of MySQL version.
Use the hyphen where it can't make part of a range construction.
Fix the expression as
SELECT * FROM customer WHERE name REGEXP "[^0-9a-zA-Z .&(),-]+";
If the entire text should match this pattern, enclose with ^ / $:
SELECT * FROM customer WHERE name REGEXP "^[^0-9a-zA-Z .&(),-]+$";
- implies a range except if it is first. (Well, after the "not" (^).)
So use
"[^-0-9a-zA-Z .&(),]"
I removed the + at the end because you don't really care how many; this way it will stop after finding one.
I'm trying to get results when both tables have the same machine number and there are entries that have the same number in both tables.
Here is what I've tried:
SELECT fehler.*,
'maschine.Maschinen-Typ',
maschine.Auftragsnummer,
maschine.Kunde,
maschine.Liefertermin_Soll
FROM fehler
JOIN maschine
ON ltrim(rtrim('maschine.Maschinen-Nr')) = ltrim(rtrim(fehler.Maschinen_Nr))
The field I'm joining on is a varchar in both cases. I tried without trims but still returns empty
I'm using MariaDB (if that's important).
ON ltrim(rtrim('maschine.Maschinen-Nr')) = ltrim(rtrim(fehler.Maschinen_Nr)) seems wrong...
Is fehler.Maschinen_Nr really the string 'maschine.Maschinen-Nr'?
SELECT fehler.*, `maschine.Maschinen-Typ`, maschine.Auftragsnummer, maschine.Kunde, maschine.Liefertermin_Soll
FROM fehler
JOIN maschine
ON ltrim(rtrim(`maschine.Maschinen-Nr`)) = ltrim(rtrim(`fehler.Maschinen_Nr`))
Last line compared a string to a number. This should be doing it.
Also, use the backtick to reference the column names.
The single quotes are string delimiters. You are comparing fehler.Maschinen_Nr with the string 'maschine.Maschinen-Nr'. In standard SQL you would use double quotes for names (and I think MariaDB allows this, too, certain settings provided). In MariaDB the commonly used name qualifier is the backtick:
SELECT fehler.*,
`maschine.Maschinen-Typ`,
maschine.Auftragsnummer,
maschine.Kunde,
maschine.Liefertermin_Soll
FROM fehler
JOIN maschine
ON trim(`maschine.Maschinen-Nr`) = trim(fehler.Maschinen_Nr)
(It would be better of course not to use names with a minus sign or other characters that force you to use name delimiters in the first place.)
As you see, you can use TRIM instead of LTRIM and RTRIM. It would be better, though, not to allow space at the beginning or end when inserting data. Then you wouldn't have to remove them in every query.
Moreover, it seems Maschinen_Nr should be primary key for the table maschine and naturally a foreign key then in table fehler. That would make sure fehler doesn't contain any Maschinen_Nr that not exists exactly so in maschine.
To avoid this problems in future, the convention for DB's is snake case(lowercase_lowercase).
Besides that, posting your DB schema would be really helpfull since i dont guess your data structures.
(For friendly development, is usefull that variables, tables and columns should be written in english)
So with this, what is the error that you get, because if table "maschine" has a column named "Maschinen-Nr" and table "fehler" has a column named "Maschinen_Nr" and the fields match each other, it should be correct
be careful with Maschinen-Nr and Maschinen_Nr. they have - and _ on purpose?
a very blind solution because you dont really tell what is your problem or even your schema is:
SELECT table1Alias.*, table2Alias.column_name, table2Alias.column_name
FROM table1 [table1Alias]
JOIN table2 [table2Alias]
ON ltrim(rtrim(table1Alias.matching_column)) = ltrim(rtrim(table2Alias.matching_column))
where matching_columns are respectively PK and FK or if the data matches both columns [] are optional and if not given, will be consider table_name
In my database I have a table called 'content' and a field called 'link' and there are almost 300,000 records in that table.
In the field called 'link' there are a number of records that look like this :
http://www.example.com/blah/blah/123456789/url=http://www.destination.com
Unfortunately the prefix part of the records are individually unique where the numbered portion is constant changing from 90 to 150 alpha-numeric characters
I would like to remove the prefix up to and/or including the url=
So that the only thing left in the record is :
http://www.destination.com OR
I could even work with
url=http://www.destination.com
and simply do a replace command against the "url=" part as a second mysql command.
If there was a wildcard command, this job would be much easier and I would just wildcard everything showing up in the link record between :
http://www.example.com/blah/blah/ wildcard url=
But as everyone knows... there is no such wildcard available
So it had me looking at the UPDATE, SET and TRIM(LEADING commands
UPDATE content
SET link =
TRIM(LEADING 'url=' FROM link)
But this DID NOT generate the changes I wanted
And so I took the labor intensive method of downloading the database and using a Search and Replace program to make the changes to the 44 thousand records that contained these parameters.
But I would love to find a command that I could simply pass to the database to make this simpler in the future.
Any thoughts on how to accomplish this change in the future would be greatly appreciated.
Thanks in advance ;
You can use the SUBSTRING_INDEX function:
UPDATE content SET link=SUBSTRING_INDEX( `link` , 'url=', -1 )
I have not tested it, so I would recommend you check that substring_index returns the desired string first.
Assuming that the part you want to keep always begins with 'http://' you could get the desired result string with the help of the SUBSTRING_INDEX function:
SELECT CONCAT('http://', SUBSTRING_INDEX(link, 'http://', -1)) FROM content;
and fix your table with the simple statement
UPDATE
content
SET
link = CONCAT('http://', SUBSTRING_INDEX(link, 'http://', -1));
Explanation:
SUBSTRING_INDEX with third parameter negative returns the substring from the last occurence of the needle in the second parameter to the end. Because 'http://' isn't included in the return value, we add it again.
Remark:
If you've got https:// urls too, you should be able to adapt my solution.
I have 2000 products with row that is using serialized data and I need to update specific string
this is the row name data
a:35:{s:11:"expire_days";s:3:"30d";s:12:"trial1_price";s:0:"";s:11:"trial1_days";s:0:"";s:12:"is_recurring";s:0:"";s:10:"start_date";s:0:"";s:5:"terms";s:24:"$150 for 1 Per license";s:12:"rebill_times";s:0:"";s:15:"paypal_currency";s:0:"";s:4:"##11";N;s:3:"url";s:0:"";s:8:"add_urls";s:0:"";s:4:"##12";N;s:5:"scope";s:0:"";s:5:"order";s:4:"1010";s:11:"price_group";s:1:"7";s:13:"renewal_group";s:2:"28";s:14:"need_agreement";s:0:"";s:13:"require_other";a:1:{i:0;s:0:"";}s:16:"prevent_if_other";N;s:4:"##13";N;s:19:"autoresponder_renew";s:0:"";s:16:"dont_mail_expire";s:0:"";s:13:"joomla_access";s:2:"36";s:10:"files_path";s:108:"products/Boxes8.zip|Box 8
products/Boxes9.zip|Box 9";s:14:"download_count";s:0:"";s:18:"download_unlimited";}
and only thing I need changed is
s:24:"$150 for 1 Per license";
any help is appreciated.
You should probably SELECT the row, make your changes, then UPDATE with the new value. The answer to this question may be helpful if you need to do this database side.
How to do a regular expression replace in MySQL?
If you want to replace the value of that single field with something else, you can use the following query:
UPDATE table SET col = CONCAT(
LEFT(col, LOCATE('s:24:"', col) + 5), -- up to and including the opening quote
'Now for free', -- new replacement text
SUBSTR(col, LOCATE('"', col, LOCATE('s:24:"', col)+6)) -- closing quote and everything after that
) WHERE col LIKE '%s:24:"$150 for 1 Per license"%'
Note that there is potential for trouble: if the value of one of your fields should end in 's:24:', then that combined with the closing quote would get misinterpreded as the location you're looking at. I consider this risk unlikely, but if you want to play it safe, you might want to check for that with an elaborate regular expression that can deal with quoted strings and escaped quotes.
I am struggling with this query and want to know if I am wasting my time and need to write a php script or is something like the following actually possible?
UPDATE my_table
SET #userid = user_id
AND SET filename('http://pathto/newfilename_'#userid'.jpg')
FROM my_table
WHERE filename
LIKE '%_%' AND filename
LIKE '%jpg'AND filename
NOT LIKE 'http%';
Basically I have 700 odd files that need renaming in the database as they do not match the filenames as I am changing system, they are called in the database.
The format is 2_gfhgfhf.jpg which translates to userid_randomjumble.jpg
But not all files in the database are in this format only about 700 out of thousands. So I want to identify names that contain _ but don't contain http (thats the correct format that I don't want to touch).
I can do that fine but now comes the tricky bit!!
I want to replace that file name userid_randomjumble.jpg with http://pathto/filename_userid.jpg So I want to set the column user_id in that row to a variable and insert it into my new filename.
The above doesn't work for obvious reasons but I am not sure if there is a way round what I'm trying to do. I have no idea if it's possible? Am I wasting my time with this and should I turn to PHP with mysql and stop being lazy? Or is there a way to get this to work?
Yes it is possible without the php. Here is a simple example
SET #a:=0;
SELECT * FROM table WHERE field_name = #a;
Yes you can do it using straightforward SQL:
UPDATE my_table
SET filename = CONCAT('http://pathto/newfilename_', userid, '.jpg')
WHERE filename LIKE '%\_%jpg'
AND filename NOT LIKE 'http%';
Notes:
No need for variables. Any columns of rows being updated may be referenced
In mysql, use CONCAT() to add text values together
With LIKE, an underscore (_) has a special meaning - it means "any single character". If you want to match a literal underscore, you must escape it with a backslash (\)
Your two LIKE predicates may be safely merged into one for a simpler query