如何从 SQL 中提取 JSON 值，其中列值有时为空

Question

I have a table with column 'sometimesjson' that somtimes contains a value like this:

[{"id":111,"nam":"PROVIDER_this_one","qty":null}]

and sometimes the field completely is empty, not just "[]" but completely empty/null field.

So I try to return "PROVIDER_this_one" with this, but errors...

CASE WHEN JSON_VALID(sometimesjson) 
            THEN 
            JSON_EXTRACT(sometimesjson, '$.nam') 
            AS 'FROMJSON' 
             ELSE null  

Any ideas?

Answer 1

I figured it out. I guess because the json value actually is an array, the correct way for me to call "nam" for every value in that table field value array was this... '$[*].nam' instead of '$.nam' it's working now with...

    CASE WHEN JSON_VALID(sometimesjson) 
            THEN 
            JSON_EXTRACT(sometimesjson, '$[*].nam') 
            AS 'FROMJSON' 
             ELSE null