How to PARSE_JSON from Snowflake Field? - sql

Question

I have a table that looks like:
ID|FIELD1
1|[ { "list": [ {} ] } ]
2|[ { "list": [ { "item": "" } ] } ]
3|[ { "list": [ { "item": "Tag1" }, { "item": "Tag2" } ] } ]
And I want to get all the tags associated to this specific query such that I can just get a list:
Tag1,Tag2
I've tried
SELECT PARSE_JSON(FIELD1[0]['list'][0]['item']) FROM MY_TABLE
WHERE PARSE_JSON(FIELD1[0]['list'][0]) != '{}'
But I get
JSON: garbage in the numeric literal: 65-310 , pos 7
How can I properly unpack these values in SQL?
UPDATE: Clumsy Solution
SELECT LISTAGG(CODES,'\',\'') AS PROMO_CODES
FROM
(SELECT DISTINCT FIELD1[0]['list'][0]['item'] AS CODES FROM MY_TABLE
WHERE FIELD1[0]['list'][0] IS NOT NULL
AND FIELD1[0]['list'][0] != '{}'
AND FIELD1[0]['list'][0]['item'] != ''
)

Answer 1

Please have a look into below knowledge article, if this helps in your case:
https://community.snowflake.com/s/article/Dynamically-extracting-JSON-using-LATERAL-FLATTEN

Answer 2

As I see, the Clumsy Solution does not provide the correct result. It shows only Tag1. So here's my solution:
select LISTAGG( v.VALUE:item, ',' ) from MY_TABLE,
lateral flatten (parse_json(FIELD1[0]):list) v
WHERE v.VALUE:item <> '';
I would recommend to add DISTINCT to prevent duplicate tags in the output:
select LISTAGG( DISTINCT v.VALUE:item, ',' ) from MY_TABLE,
lateral flatten (parse_json(FIELD1[0]):list) v
WHERE v.VALUE:item <> '';
If there are more items in the FIELD1 array (ie 0,1,2), you may use this one:
select LISTAGG( DISTINCT v.VALUE:item, ',' ) from MY_TABLE,
lateral flatten(FIELD1) f,
lateral flatten (parse_json(f.VALUE):list) v
WHERE v.VALUE:item <> '';