So, I have a list of "whitelisted" countries (eg. ['PT', 'US', 'UK', 'ES']) on a column of a table, and I want to check if the user's country (eg. 'US') is whitelisted, in order to show the user the row's content.
I searched and the best and easiest way I found was to compile the whitelisted list into a JSON array, make the column JSON type and use the JSON_CONTAINS function present on MySQL 5.7+
However, I can't figure out how to implement that with CI's database library.
How can I use CI's DB lib to use MySQL's functions? Would there be a better way to achieve this instead of JSON array?
You can use
$this->db->where("(JSON_CONTAINS(field,'[\"US\"]')) > ",0);
The codeigniter where clause required an operator. If we provide an operator codeigniter will ignore IS NULL
Related
I have a table in MySQL where each row contains JSON returned from another system. The JSON will look something like:
[{"userId": "Dave"},{"userId": "Mary", "errorCode" : "DB Fail"}, {"userId": "Lorenza", "errorCode": "Web Error"}]
and I'm only interested in the members of the array containing an error code. In the future, these will be parsed into seperate rows of their own table, but in the meantime does MySql offer a way to extract only these with an errorCode?
I can use JSON_EXTRACT to extract the errorCodes only
JSON_EXTRACT(jsonData, '$[*].errorCode') AS errorCodes
but I really want the rest of the member (userId in the example above)
You could use the JSON_CONTAINS function to find the records with errorCode and then then use JSON_EXTRACT on those records. Put the JSON_CONTAINS in the where clause
I don't think you could do this with a single query without known boundaries of the number of elements, but you could use a stored procedure to run a loop.
e.g. each iteration runs LOCATE to find the position of "errorCode", and uses that location to run SUBSTR and/or SUBSTRING_INDEX to get the userid value and append it to another variable. The looped variable would just be the offset used in the LOCATE query.
I have an JSON string stored in the database and I need to SQL COUNT based on the WHERE condition that is in the JSON string. I need it to work on the MYSQL 5.5.
The only solution that I found and could work is to use the REGEXP function in the SQL query.
Here is my JSON string stored in the custom_data column:
{"language_display":["1","2","3"],"quantity":1500,"meta_display:":["1","2","3"]}
https://regex101.com/r/G8gfzj/1
I now need to create a SQL sentence:
SELECT COUNT(..) WHERE custom_data REGEXP '[HELP_HERE]'
The condition that I look for is that the language_display has to be either 1, 2 or 3... or whatever value I will define when I create the SQL sentence.
So far I came here with the REGEX expression, but it does not work:
(?:\"language_display\":\[(?:"1")\])
Where 1 is replaced with the value that I look for. I could in general look also for "1" (with quotes), but it will also be found in the meta_display array, that will have different values.
I am not good with REGEX! Any suggestions?
I used the following regex to get matches on your test string
\"language_display\":\[(:?\"[0-9]\"\,)*?\"3\"(:?\,\"[0-9]\")*?\]
https://regex101.com/ is a free online regex tester, it seems to work great. Start small and work big.
Sorry it doesn't work for you. It must be failing on the non greedy '*?' perhaps try without the '?'
Have a look at how to serialize this data, with an eye to serializing the language display fields.
How to store a list in a column of a database table
Even if you were to get your idea working it will be slow as fvck. Better off to process through each row once and generate something more easily searched via sql. Even a field containing the comma separated list would be better.
I am not a seasonal Windows user, I got a task wherein I had to query the Window Index search table i.e "Systemindex" for fetching some user specific data from the db.
And for this I have to match a pattern basically a regular expression while fetching the data.
SELECT System.FileName, System.ItemPathDisplay, System.DateCreated, System.DateModified, System.ItemName, System.KindText FROM Systemindex WHERE Contains('“(?=^[A-Za-z\d!##\$%\^&\*\(\)_\+=]{9,32}$)”');
The above would allow us to search for say stored passwords.
But when I query the db using the below command I was getting an error. And later I came to know that the "contains" clause
does not support regular expression. Is there an alternative to achieve this?
there is REGEXP operator http://dev.mysql.com/doc/refman/5.7/en/regexp.html,
use smth like this
SELECT * FROM Systemindex WHERE some_column REGEXP 'your_regex'
I am creating a query to re-use periodically to pull data out of a MySQL database (not for use in production code) and want to display values from a JSON object as columns. I installed common_schema and have been using the extract_json function but I can't find the correct xpath to use to get the field I want, I always get null. The query I am using currently is below:
SELECT common_schema.extract_json_value(stores.info,'/Region') as "Sales Region" FROM stores
An example of the JSON object stored in stores.info is below:
{"Town":"HDM","Post Code":"003408","Region":"FGH","OutletCode":"AB43G","CustomerCode":"15134158"}
What xpath do I need to access, for example Region. If the path is correct why is it returning NULL?
I am storing values in database like this
www/content/lessons/40/Digital Library/document1.doc
I need to extract the file document.doc.
How to retrieve this value from mysql using regular expression.
you not need to use regexp (low performence)
use substring_index instead
SELECT SUBSTRING_INDEX('bbb/bbbbbb/bbbbbbbbb/bbbb', '/', -1);
link :
http://dev.mysql.com/doc/refman/5.1/en/string-functions.html#function_substring-index
Mysql does not provide regex based extraction from strings, but you can extend mysql to do this:
https://github.com/mysqludf/lib_mysqludf_preg
It's not a good solution for a lot of people though. eg you couldn't use it in a shared hosting environment.