I have a column that looks like:
[{"key_1":true,"key_2":true,"key_3":false},{"key_1":false,"key_2":false,"key_3":false},...]
There can be 1 to many items described by parameters in {} in the column.
I would like to extract values only of parameters described by key_1. Is there a function for that? I tried so far json related functions (json_tuple, get_json_object) but each time I received null.
Consider below json path.
WITH sample_data AS (
SELECT '[{"key_1":true,"key_2":true,"key_3":false},{"key_1":false,"key_2":false,"key_3":false}]' json
)
SELECT get_json_object(json, '$[*].key_1') AS key1_values FROM sample_data;
Query results
Related
Lets consider the following table on Google BigQuery:
WITH example AS (
SELECT 1 AS id, ["{\"id\":1, \"name\":\"AAA\"}", "{\"id\":2, \"name\":\"BBB\"}","{\"id\":3, \"name\":\"CCC\"}"]
UNION ALL
SELECT 2 AS id, ["{\"id\":5, \"name\":\"XXX\"}", "{\"id\":6, \"name\":\"ZZZ\"}"]
)
SELECT *
FROM example;
I would like to compose a query that will return names with their parent row's id.
like:
I tried using unnest with json functions and I just cant make this right.
Can anyone help me?
Thanks
Ido
According to your query, you already have json elements in your array. So with the use of unnest, you can use a json function like json_value to extract the name attribute of your elements.
select
id,
json_value(elt, '$.name')
from example, unnest(r) as elt;
I am querying a BigQuery table to extract building data. We are storing building data in a cell, together with location and sensor name data. The building row has the following values e.g.
GB-FRE-BB2003_MSU-01
GB-FRE-BB2001_MSU-12
GB-FRE-BB2003_MSU-12
GB-FRE-BB2012_MSU-12
GB-FRE-BB2003_MSU-10
etc
I would like to query the data, using a substring, so I can find all the data from the BD2003 building, regardless of location and sensor.
SELECT `presentvalue`
FROM `database`
WHERE ???
Is someone able to help with this? I have looked at SPLIT and SUBSTRING but can't seem to get the query right.
Few more options
Using LIKE
select *
from your_table
where presentvalue like '%-BB2003_%'
Using REGEXP_CONTAINS
select *
from your_table
where regexp_contains(presentvalue, '-BB2003_')
if applied to sample data in your question - both have below output
use where substring(split(val , '-')[offset(2)], 1, 6)='BB2003'
tested it on the below code and it works:
create temp table sample(
val string
);
insert into sample
(val)
values
('GB-FRE-BB2003_MSU-01'),
('GB-FRE-BB2001_MSU-12'),
('GB-FRE-BB2003_MSU-12'),
('GB-FRE-BB2012_MSU-12'),
('GB-FRE-BB2003_MSU-10');
select *, from sample where substring(split(val , '-')[offset(2)], 1, 6)='BB2003''
I have string column that looks usually approximately like this:
https://mapy.cz/zakladni?x=16.3360208&y=49.6718038&z=8&source=firm&id=13123554
https://mapy.cz/turisticka?x=15.9380354&y=50.1990211&z=11&source=base&id=2197
https://mapy.cz/turisticka?x=12.8611357&y=49.8051338&z=16&source=base&id=1703157
I would like to group data by source which is part of the string - four letters behind "source=" (in the case above: firm) and then simply count them. Is there a way to achieve this directly in SQL code? I am using hadoop.
Data is a set of strings that look like above. My expected result is summary table with two columns: 1) Each type of the source (there is about 20 possible and their length is different so I cannot use sipmle substring). Ideally I am looking for solution that says: For the grouping use four letters that come after "source=" 2) Count of their occurences in all the strings.
There is just one source type in each string.
You can use regexp_extract():
select substr(regexp_extract(url, 'source[^&]+'), 8)
You can use charindex in MSSQL to get position of string and extract record
;with cte as (
SELECT SUBSTRING('https://mapy.cz/zakladni?x=16.3360208&y=49.6718038&z=8&source=firm&id=13123554',
charindex('&source=','https://mapy.cz/zakladni?x=16.3360208&y=49.6718038&z=8&source=firm&id=13123554')
+8,4) AS ExtractString )
select ExtractString,count(ExtractString) as count from cte group by ExtractString;
There is equivalent function LOCATE in hiveql for charindex.
I would like to convert this table
to something like this
the long string can be dynamic so it's important to me that it's not a fixed solution for these values specifically
Please help, i'm using big query
You could start by using SPLIT SPLIT(value[, delimiter]) to convert your long string into separate key-value pairs in an array.
This will be sensitive to you having commas as part of your values.
SPLIT(session_experiments, ',')
Then you could either FLATTEN that array or access each element, and then use some REGEXs to separate the key and the value.
If you share more context on your restrictions and intended result I could try and put together a query for you that does exactly what you want.
It's not possible what you want, however, there is a better practice for BigQuery.
You can use arrays of structs to store that information in a table.
Let's say you have a table like that
You can use that sample query to understand how to use it.
with rawdata AS
(
SELECT 1 as id, 'test1-val1,test2-val2,test3-val3' as experiments union all
SELECT 1 as id, 'test1-val1,test3-val3,test5-val5' as experiments
)
select
id,
(select array_agg(struct(split(param, '-')[offset(0)] as experiment, split(param, '-')[offset(1)] as value)) from unnest(split(experiments)) as param ) as experiments
from rawdata
The output will look like that:
After having that output, it's more convenient to manipulate the data
I have some data in a postgres table that is a string representation of an array of json data, like this:
[
{"UsageInfo"=>"P-1008366", "Role"=>"Abstract", "RetailPrice"=>2, "EffectivePrice"=>0},
{"Role"=>"Text", "ProjectCode"=>"", "PublicationCode"=>"", "RetailPrice"=>2},
{"Role"=>"Abstract", "RetailPrice"=>2, "EffectivePrice"=>0, "ParentItemId"=>"396487"}
]
This is is data in one cell from a single column of similar data in my database.
The datatype of this stored in the db is varchar(max).
My goal is to find the average RetailPrice of EVERY json item with "Role"=>"Abstract", including all of the json elements in the array, and all of the rows in the database.
Something like:
SELECT avg(json_extract_path_text(json_item, 'RetailPrice'))
FROM (
SELECT cast(json_items to varchar[]) as json_item
FROM my_table
WHERE json_extract_path_text(json_item, 'Role') like 'Abstract'
)
Now, obviously this particular query wouldn't work for a few reasons. Postgres doesn't let you directly convert a varchar to a varchar[]. Even after I had an array, this query would do nothing to iterate through the array. There are probably other issues with it too, but I hope it helps to clarify what it is I want to get.
Any advice on how to get the average retail price from all of these arrays of json data in the database?
It does not seem like Redshift would support the json data type per se. At least, I found nothing in the online manual.
But I found a few JSON function in the manual, which should be instrumental:
JSON_ARRAY_LENGTH
JSON_EXTRACT_ARRAY_ELEMENT_TEXT
JSON_EXTRACT_PATH_TEXT
Since generate_series() is not supported, we have to substitute for that ...
SELECT tbl_id
, round(avg((json_extract_path_text(elem, 'RetailPrice'))::numeric), 2) AS avg_retail_price
FROM (
SELECT *, json_extract_array_element_text(json_items, pos) AS elem
FROM (VALUES (0),(1),(2),(3),(4),(5)) a(pos)
CROSS JOIN tbl
) sub
WHERE json_extract_path_text(elem, 'Role') = 'Abstract'
GROUP BY 1;
I substituted with a poor man's solution: A dummy table counting from 0 to n (the VALUES expression). Make sure you count up to the maximum number of possible elements in your array. If you need this on a regular basis create an actual numbers table.
Modern Postgres has much better options, like json_array_elements() to unnest a json array. Compare to your sibling question for Postgres:
Can get an average of values in a json array using postgres?
I tested in Postgres with the related operator ->>, where it works:
SQL Fiddle.