Selecting rows in mySQL table by comparing the value to python dictionary - mysql

I have 2 databases one in mongoDB and one table in mySQL. I am taking data from mongoDB which is being stored in a dictionary and looks like this-
dictionary = {
"message_code": "12345"
}
I want to match this message_code value in the mySQL tables colums called final_code and retrieve table rows which match the message_code. How can I do that?
SELECT *
FROM mysql_table
WHERE final_code = dictionary.message_code
Something like this?


You pass a string to mysql, not python objects. So you must build that string interpolating the values you want in python, i.e.
'SELECT * FROM mysql_table WHERE final_code='+dictionary["message_code"]
and pass that string to mysql as query.

Related

How do I extract values from a JSON array in MariaDB or MySQL?

Situation
I have a table in a MariaDB database. This table has a LONGTEXT column which is used to store a JSON array (read more about this topic in MariaDB JSON Data Type).
Question
I would like to extract values from the JSON array, based on a certain key. How do I achieve this with MariaDB (or MySQL)?
Example
Here's the simplified table thing (just for demo purposes):
id
thing_name
examples
0
fruit
[{"color": "green","title": "Apple"},{"color": "orange","title": "Orange"},{"color": "yellow","title": "Banana"}]
1
car
[{"color": "silver","title": "VW"},{"color": "black","title": "Bentley"},{"color": "blue","title": "Tesla"}]
My goal is to extract all title values from the JSON array.

You can use JSON_EXTRACT for this task (works for both MariaDB and MySQL). This function also supports wildcards, as described in the docs:
Paths can contain * or ** wildcards
Depending on whether you have multiple levels of data (e.g. single document vs array), either a single or double asterisk wildcard should be used:
JSON_EXTRACT(json,'$**.key')
json is a valid JSON document (e.g. a column), key is the lookup key used.
For your example
In order to find all title values in your JSON array, use the following query:
SELECT id, thing_name, JSON_EXTRACT(examples, '$**.title') as examples_titles FROM thing
id
thing_name
examples_titles
0
fruit
["Apple", "Orange", "Banana"]
1
car
["VW", "Bentley", "Tesla"]

Get Column names of MySQL table with PDO

I'm trying to write a function that returns an array of column names for a MySQL table.
When I use something like this in HeidiSQL
SELECT COLUMN_NAME FROM information_schema.COLUMNS
WHERE table_schema = 'myDB'
AND TABLE_NAME = 'myTable'
I get exactly what I want. A single column of output showing the column names.
when I took the above code and used it in a PHP program using PDO calls every array value is of the format:
string(xx) "column_name"
I do not want the leading "string(xx)" in front of the column name.
I'm using the pdo function as follows:
fetchAll(PDO::FETCH_COLUMN)
I don't see other PDO fetch options to just give me the column names, without the leading "string(xx)" value.
I could parse the results and strip the leading string(xx) value, but I was wondering if there's an easier/better trick.

Oh, mental lapse... as I dug deeper into my output array, I was thrown off by my output because I was using var_dump. var_dump prefaces the values with the "string(xx)" value. MySQL isn't the one putting the "string(xx)" prefix.
Live and learn...

MySQL Query - Convert ResultSet to JSON

I need to convert select * from {table_name} into JSON output.Instead of specifying separate key-value pair in 'JSON_OBJECT'.
I have tried this query
select JSON_ARRAYAGG(json_object("col_name_1",alias.column_1,"col_name_2",alias.column_2)) from {table_name} alias;
This one is giving me results what I need, but my question is instead of giving as key-value pair in json_object I need to fetch all columns by giving something like '*'.
MySQL Database Version: 5.7.24

Updating one row in JSON stored in MySQL

I've got a longtext field in my MySQL database that contains JSON strings. I'd like to be able to update only one row in the string rather than have to reinsert the entire thing updated.
How can I do that? I'm using Laravel but could do a raw query if needed.
(This is the first time I'm using JSON, so if I'm not using the right terminolgoy, forgive me.)

Your column needs to be of json type. then you can use the JSON_SET to set a aprticular json key in your payload.
example :
update table SETjson_column= JSON_SET(json_column, '$.\"$key\"' , 'foo') where id = 1;

Mysql JSON Multi-dimensional Array

which form should have json code in mysql field ?
I need users datas (user_id is the key) with 3 values (3 informations : name , age, sex)
145:"name,age,sex",
148:"name,age,sex",
200:"name,age,sex"
I am using mysql version 5.6 and the datas will be inserted with SQL code
is it correct to store it in that way in mysql to retrieve with php and json_decode?
[{236:"paul,26,1"},{2515:"fred,42,1"},{2515:"jane,21,0"}]
thank you

Do you ever want to be able to write a query like select * from users where sex=1? If so, don't store the JSON as text. Store each value (id, name, age, sex) in a column of its own.
Even if you do want to store the JSON as a string, it would probably be better organised like this:
[
{"id":236,"name":"paul","age":26,"sex":1},
{"id":2515,"name":"fred","age":42,"sex":1},
{"id":2516:"jane","age":21,"sex":0}
]
You would need to manipulate it a bit after querying, but you would have more meaningful data.
But if all you want is to store that text, so you can retrieve it as text later, then what you have is fine.

with datas in this form
[{236:"paul,26,1"},{2515:"fred,42,1"},{2515:"jane,21,0"}]
and json_decode($myfield);
I get NULL
if I echo $myfield I get exatly what is stored in the database
what is wrong with N
[{236:"paul,26,1"},{2515:"fred,42,1"},{2515:"jane,21,0"}]
If I parse it here http://json.parser.online.fr/
I get Syntax error