# Query to extract data from MariaDB using SELECT statement to link with the RFID card detected
**URL:** https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497
**Category:** General
**Created:** [9 October 2019 09:07 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497 "2019-10-09T09:07:31Z")
**Posts on this page:** 11
**Page:** 3
### Author:  [@primat11](https://discourse.nodered.org/u/primat11)
#### Post date: [10 October 2019 10:29 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/42 "2019-10-10T10:29:17Z")
Thanks @kuema for your detailed explanation. I have tried exactly like you suggested and have shared my below findings of the three debug nodes from the flow that I have.
Please see to it, the data from the database is still not getting extracted. You might get a clear view from the screenshots.
  
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### Author:  [@kuema](https://discourse.nodered.org/u/kuema)
#### Post date: [10 October 2019 10:30 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/43 "2019-10-10T10:30:53Z")
Your function node has two outputs, please use only one directly linked to the database node and try again 😉
(I mean, you have to actually set the number of outputs to 1 again. Using multiple outputs is not needed here)
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### Author:  [@primat11](https://discourse.nodered.org/u/primat11)
#### Post date: [10 October 2019 10:37 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/44 "2019-10-10T10:37:17Z")
Thanks a lot, I just did that and now the problem is solved. Grateful to you and everyone who has helped in this matter. 🙂
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### Author:  [@primat11](https://discourse.nodered.org/u/primat11)
#### Post date: [10 October 2019 10:39 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/45 "2019-10-10T10:39:08Z")
Just one last question : Has it got anything with Primary key in the database to do? Is it necessary that the column name in the query must be a primary key in the database?
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### Author:  [@kuema](https://discourse.nodered.org/u/kuema)
#### Post date: [10 October 2019 10:42 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/46 "2019-10-10T10:42:36Z")
No, not for functionality. But for performance reasons I would use proper indexes on columns that are part of conditions in your queries.
In most database systems the primary key is indexed by default, so adding one on `uID` would be a good idea. (I don't know enough about your table structure for a precise answer)
At least an index on `uID` would be recommended.
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### Author:  [@primat11](https://discourse.nodered.org/u/primat11)
#### Post date: [10 October 2019 10:51 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/47 "2019-10-10T10:51:59Z")
I changed the column uID to primary key before trying any further implementations as I thought it could also be the reason.
Thanks for your guidance and sharing knowledge. Have a nice day 🙂
Regards
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [10 October 2019 16:11 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/48 "2019-10-10T16:11:35Z")
Just to clear up why this did not replace ${msg.payload} with the value from the payload. It is because, as I said in my last post and as detailed in the link I posted you need to use backticks not double quotes to use this form of string interpollation.
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### Author:  [@primat11](https://discourse.nodered.org/u/primat11)
#### Post date: [11 October 2019 08:08 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/49 "2019-10-11T08:08:27Z")
@Colin Thanks again for your reply. I understand exactly now what you mean, I am sorry that I somehow could not try exactly like you suggested as being a beginner I got a bit confused. I am sure it is gonna work too. Thanks for your efforts, means a lot 🙂
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### Author:  [@shipra](https://discourse.nodered.org/u/shipra)
#### Post date: [16 July 2020 07:36 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/50 "2020-07-16T07:36:19Z")
how you have connected your database (mssql) with node red please tell
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### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [16 July 2020 08:51 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/51 "2020-07-16T08:51:29Z")
@shipra - this is a thread that is 9 months old and about MariaDB not mssqj. Please stick to your original thread.
I am closing this thread.
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### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [16 July 2020 08:51 UTC](https://discourse.nodered.org/t/query-to-extract-data-from-mariadb-using-select-statement-to-link-with-the-rfid-card-detected/16497/52 "2020-07-16T08:51:34Z")
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