First let me apologize I have not been successful in finding anything online with this specific scenario.
I have been using MySQL for quite some time, but I am hoping to get some clarification on a certain situation I have come across, which honestly bothers me quite a bit.
I'm trying to match a string in a MySQL column that contains both \ and % literal characters using the LIKE operator.
Inside the table I have two records:
id value
-----------------------
1 100\\%A
2 100\%A
They both contain literal special characters.
If I do a SELECT, in an attempt to only match the first record (id=1), I would expect to write the query as such:
SELECT * FROM table_name WHERE value LIKE '%0\\\\\%A'
(\\\\ to match two literal backslashes, plus a backslash before % to match a literal %)
However, It only matches the row (id=2), which makes no sense to me.
If I change the query a little to be:
SELECT * FROM table_name WHERE value LIKE '%0\\\\%A'
I would expect to match the id=1 row only, (\\\\ to match 2 literal backslashes, and the % is not literal and should represent a wildcard). But instead, it matches both rows?
row (id=2) only has a single backslash but still matches.
Is row id=2 matching because the first 2 backslashes are matching the \, the 3rd backslash is ignored for some reason, and the 4th backslash is allowing a literal match on the %?
If I do a:
SELECT * FROM table_name WHERE value LIKE '%0\\\\\\\%A'
I for some reason get row (id=1), when I would expect to get no matches whatsoever.
I'm trying to find a solution in which I can do partial matches on any series of characters accurately, including those with consecutive special characters such as the scenario above. However, I'm having an impossible time trying to plan for situations such as these.
Any input would be greatly appreciated.
Maybe this help you understand the usage of escape chars in mySQL
https://stackoverflow.com/a/27061961/634698
I have a column in an SQL table populated with the contents of an entire text file. Is there a way to get all substring matches of a particular term? For example, I want to get all occurrences of the words "bright star" starting 10 characters before the first occurrence and ending 10 characters after.
I was trying things like this with no success:
SELECT SUBSTRING (PARAGRAPH, -10, 10)
WHERE MATCH (paragraph) AGAINST ("+bright +star" IN BOOLEAN MODE);
I know that MySQL queries can be deeply nested, but I don't know if it's even possible to perform such a search.
Many thanks,
A.
You want to use Regular Expressions to filter out subtring matches by your pattern.
SELECT REGEXP_SUBSTR(paragraph, '.{10}[bright|star].{10}')
So I have a table called "lu_regex" with a column called "regex"
Select * from lu_regex;
athedsl-\d+
i5[93][0-9a-fA-F]+\.versa
5ac[a-f0-9]+.+sky
The table contains 1000's of rows, with various Regular Expressions syntax, i'm just showing three in this example.
Now I'm trying to take user input and match that input against the rows in the table. So I'm doing this.
SELECT * FROM lu_regex where '5aca3a11.bb.sky.comr' regexp regex;
regex
5ac[a-f0-9]+.+sky
1 row returned.
I'm getting back what I expected, with that query, then I try this one.
SELECT * FROM lu_regex where 'athedsl-07371.home.otenet.gr' regexp regex;
0 rows returned.
It should match on "athedsl-\d+", but i'm assuming it has something to do with the "\d". I even tried adding this to the database "athedsl-\\d+" and that didn't cause a match either.
I'm trying to stick to a MySQL solution, what am I doing wrong, this should be possible.
I just found this link, it looks like a bug that hasn't been fixed. It was verified in 2013.
https://bugs.mysql.com/bug.php?id=70413
Bug #70413 \d is not working in REGEXP for a MySQL query
I think the solution is going to be is to replace all \d with [0-9]
I need to search for a value like 1234-abc. The database doesn't have this particular value, but has another value 1234. Now the problem is when I write my query like
SELECT * FROM words WHERE tval='1234-abc'
instead of fetching an empty recordset, it fetches the 1234 value, it seems to ignore anything after the -, any idea what's going on?
http://sqlfiddle.com/#!2/9de62/3
You can use the BINARY keyword for the exact match
SELECT tval FROM words WHERE BINARY tval='1223-abc';
Binary is a built-in keyword that after your WHERE clause that forces a comparison for an exact case-sensitive match
Fiddle
The existing expression is implicitly converting the string expression to a number - you need to explicitly convert the number to a character strng, like so:
SELECT tval FROM words WHERE convert(tval,char(20))='1223-1ABCDE';
SQLFiddle here.
I have two databases, both containing phone numbers. I need to find all instances of duplicate phone numbers, but the formats of database 1 vary wildly from the format of database 2.
I'd like to strip out all non-digit characters and just compare the two 10-digit strings to determine if it's a duplicate, something like:
SELECT b.phone as barPhone, sp.phone as SPPhone FROM bars b JOIN single_platform_bars sp ON sp.phone.REGEX = b.phone.REGEX
Is such a thing even possible in a mysql query? If so, how do I go about accomplishing this?
EDIT: Looks like it is, in fact, a thing you can do! Hooray! The following query returned exactly what I needed:
SELECT b.phone, b.id, sp.phone, sp.id
FROM bars b JOIN single_platform_bars sp ON REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(b.phone,' ',''),'-',''),'(',''),')',''),'.','') = REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(sp.phone,' ',''),'-',''),'(',''),')',''),'.','')
MySQL doesn't support returning the "match" of a regular expression. The MySQL REGEXP function returns a 1 or 0, depending on whether an expression matched a regular expression test or not.
You can use the REPLACE function to replace a specific character, and you can nest those. But it would be unwieldy for all "non-digit" characters. If you want to remove spaces, dashes, open and close parens e.g.
REPLACE(REPLACE(REPLACE(REPLACE(sp.phone,' ',''),'-',''),'(',''),')','')
One approach is to create user defined function to return just the digits from a string. But if you don't want to create a user defined function...
This can be done in native MySQL. This approach is a bit unwieldy, but it is workable for strings of "reasonable" length.
SELECT CONCAT(IF(SUBSTR(sp.phone,1,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,1,1),'')
,IF(SUBSTR(sp.phone,2,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,2,1),'')
,IF(SUBSTR(sp.phone,3,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,3,1),'')
,IF(SUBSTR(sp.phone,4,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,4,1),'')
,IF(SUBSTR(sp.phone,5,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,5,1),'')
) AS phone_digits
FROM sp
To unpack that a bit... we extract a single character from the first position in the string, check if it's a digit, if it is a digit, we return the character, otherwise we return an empty string. We repeat this for the second, third, etc. characters in the string. We concatenate all of the returned characters and empty strings back into a single string.
Obviously, the expression above is checking only the first five characters of the string, you would need to extend this, basically adding a line for each position you want to check...
And unwieldy expressions like this can be included in a predicate (in a WHERE clause). (I've just shown it in the SELECT list for convenience.)
MySQL doesn't support such string operations natively. You will either need to use a UDF like this, or else create a stored function that iterates over a string parameter concatenating to its return value every digit that it encounters.