I don't find a solution to query an array of json object with redshift. For each row, I have an array of json object stored in a column as the following:
[{'a':x,'b':y,'type':z},{'a':x,'b':y,'type':w},{'a':x,'b':y,'type':z},{a:x,b:y,type:z}]
For each row, I want to extract the number of 'type' z object in a new column. Anyone would have an idea?
Thanks a lot,
Nicolas
I've used this syntax to loop through json arrays in redshift fields.
CREATE TEMP TABLE seq
(i int); INSERT INTO seq VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8);
SELECT distinct
json_extract_path_text(json_extract_array_element_text(yourfieldname, seq.i),'type') as type
FROM yourtablename, seq AS seq
--- arman why is this less than the array
WHERE seq.i < JSON_ARRAY_LENGTH(yourfieldname)
;
DROP TABLE seq;
I've found more recent information on this. You can now use the following syntax according to the AWS Redshift documentation:
CREATE TABLE bar AS SELECT json_parse('{"scalar_array": [1, 2.3, 45000000]}') AS data;
SELECT index, element FROM bar AS b, b.data.scalar_array AS element AT index;
https://docs.aws.amazon.com/redshift/latest/dg/query-super.html
