How to check if array contains an item in JSON column using Sqlite? - sql

Question

I'm using sqlite to store JSON data that I have no control over. I have a logs table that looks like this.
id
value
s8i13s85e8f34zm8vikkcv5n
{"key":["a","b"]}
m2abxfn2n9pkyc9kjmko5462
{"key": "sometext"}
Then I use the following query to get the rows where value.key contains a:
SELECT * FROM logs WHERE EXISTS (SELECT * FROM json_each(json_extract(logs.value,'$.key')) WHERE json_each.value = 'a')
The query works fine if key is an array or if it doesn't exist. But it fails if is a string (like the second row of the table)
The error I get is:
SQL error or missing database (malformed JSON)
And it is because json_each throws if the parameter is an string.
Because of the requirements I can't control the user data or the queries.
Ideally I would like to figure out a query that either doesn't fail or that detects that the value is a string instead of an array and uses LIKE to see if the string contains 'a'.
Any help would be appreciated. Happy holidays :)

Answer 1

Use a CASE expression in the WHERE clause which checks if the value is an array or not:
SELECT *
FROM logs
WHERE CASE
WHEN value LIKE '{"key":[%]}' THEN
EXISTS (
SELECT *
FROM json_each(json_extract(logs.value,'$.key'))
WHERE json_each.value = 'a'
)
ELSE json_extract(value,'$.key') = 'a'
END;
See the demo.