I have a somewhat complicated SUPER array that I brought in to Redshift using a REST API. The 'API_table' currently looks like this:table example
One of the sample columns "values" reads as follows:
values
[{"value":[{"value":"6.9","qualifiers":["P"],"dateTime":"2023-01-30T17:30:00.000-05:00"},{"value":"6.9","qualifiers":["P"],"dateTime":"2023-01-30T17:45:00.000-05:00"},{"value":"6.9","qualifiers":["P"],"dateTime":"2023-01-30T18:00:00.000-05:00"},{"value":"6.9","qualifiers":["P"],"dateTime":"2023-01-30T18:15:00.000-05:00"},,{"value":"6.8","qualifiers":["P"],"dateTime":"2023-01-30T20:00:00.000-05:00"},...
I've queried the "value" data using:
SELECT c.values[0].value[0].value as v
FROM API_table c;
However, this only returns the first value "6.9" in each row and not all the "value" items in the row. The same approach doesn't work for extracting the "dateTime" items as it produced NULL values:
SELECT c.values[0].value[0].dateTime as dt
FROM API_table c;
The above example only resembles one row of the table. My question is-- are there ways to query the data in every row of the table so that all the values ("value" & "dateTime") of every row can be extracted onto a new table?
The desired result is:
| v | dt |
|---|---|
| 6.9 | 2023-01-30T17:45:00.000-05:00 |
| 6.9 | 2023-01-30T18:00:00.000-05:00 |
| 6.9 | 2023-01-30T18:15:00.000-05:00 |
Many thanks.
I tried the following query but it only returned singular "value' results for each row.
SELECT c.values[0].value[0].value as v
FROM API_table c;
When applied to the "dateTime" items, it yielded NULL values:
SELECT c.values[0].value[0].dateTime as dt
FROM API_table c;
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@BillWeiner thanks, I worked through both the CTE and test case examples and got the desired results (especially with CTE). The only issue that remains is knowing how to select the original table/column that contains the entire super array so that it can be inserted into test1 (or col1 in the CTE case).
There are super arrays in every row of column 'values' so the issue remains in selecting the column 'values' and extracting each of the multiple value ("6.9") and dateTime objects from each row.
================================================================
I've managed to get the query going when the json strings are explicitly stated in the insert into test1 values query.
Now I'm running this query:
SET enable_case_sensitive_identifier TO true;
create table test1 (jvalues varchar(2048));
insert into test1 select c.values from ph_api c;
create table test2 as select json_parse(jvalues) as svalues from test1;
with recursive numbers(n) as
( select 0 as n
union all
select n + 1
from numbers n
where n.n < 20
),
exp_top as
( select c.svalues[n].value
from test2 c
cross join numbers n
)
,
exp_bot as
( select c.value[n]
from exp_top c
cross join numbers n
where c.value is not null
)
select *, value.value as v, value."dateTime" as dt
from exp_bot
where value is not null;
However, I'm getting an error--ERROR: column "jvalues" is of type character varying but expression is of type super Hint: You will need to rewrite or cast the expression. when I try to insert the source table with insert into test1 SELECT c.values from table c;
I would like to be able to SELECT this source data:
| sourceinfo | variable | values |
|---|---|---|
| {"siteName":"YAN","siteCode":[{"value":"01"}] | {“variableCode":[{"value":"00600","network":"ID"} | [{“value":[{"value":"3.9","qualifiers":["P"],"dateTime":"2023-01-30T17:30:00.000-05:00"},{"value":"4.9","qualifiers":["P"],"dateTime":"2023-01-30T17:45:00.000-05:00"}] |
| {"siteName":"YAN","siteCode":[{"value":"01"}] | {“variableCode":[{"value":"00600","network":"ID"} | [{“value":[{"value":"5.9","qualifiers":["P"],"dateTime":"2023-01-30T18:00:00.000-05:00"},{"value":"6.9","qualifiers":["P"],"dateTime":"2023-01-30T18:15:00.000-05:00"}] |
as the jvalues so that it could be unrolled into a desired result of:
| v | dt |
|---|---|
| 3.9 | 2023-01-30T17:30:00.000-05:00 |
| 4.9 | 2023-01-30T17:45:00.000-05:00 |
| 5.9 | 2023-01-30T18:00:00.000-05:00 |
| 6.9 | 2023-01-30T18:15:00.000-05:00 |
================================================================
The following query worked to select the desired json strings:
with exp_top as
( select s.value
from <source_table> c, c.values s
)
select s.value, s."dateTime" from exp_top c, c.value s;
