I have a MySQL database and one of the tables is called 'my_table'. In this table, one of the columns is called 'my_json_column' and this column is stored as a JSON object in MySQL. The JSON object has about 17 key:value pairs (see below). I simply want to return a "slimmed-down" JSON Object from a MySQL query that returns 4 of the 17 fields.
I have tried many different MySQL queries, see below, but I can't seem to get a returned subset JSON Object. I am sure it is simple, but I have been unsuccessful.
Something like this:
SELECT
json_extract(my_json_column, '$.X'),
json_extract(my_json_column, '$.Y'),
json_extract(my_json_column, '$.KB'),
json_extract(my_json_column, '$.Name')
FROM my_table;
yields:
5990.510000 90313.550000 5990.510000 "Operator 1"
I want to get this result instead (a returned JSON Object) with key value pairs:
[ { X: 5990.510000, Y: 90313.550, KB: 2105, Name: "Well 1" } ]
Sample data:
{
"Comment" : "No Comment",
"Country" : "USA",
"County" : "County 1",
"Field" : "Field 1",
"GroundElevation" : "5400",
"Identifier" : "11435358700000",
"Interpreter" : "Interpreter 1",
"KB" : 2105,
"Name" : "Well 1",
"Operator" : "Operator 1",
"Owner" : "me",
"SpudDate" : "NA",
"State" : "MI",
"Status" : "ACTIVE",
"TotalDepth" : 5678,
"X" : 5990.510000,
"Y" : 90313.550
}
Thank you in advance.
Use JSON_OBJECT(), available since MySQL 5.6:
Evaluates a (possibly empty) list of key-value pairs and returns a JSON object containing those pairs
SELECT
JSON_OBJECT(
'X', json_extract(my_json_column, '$.X'),
'Y', json_extract(my_json_column, '$.Y'),
'KB', json_extract(my_json_column, '$.KB'),
'Name', json_extract(my_json_column, '$.Name')
) my_new_json
FROM my_table;
This demo on DB Fiddle with your sample data returns:
| my_new_json |
| ----------------------------------------------------------- |
| {"X": 5990.51, "Y": 90313.55, "KB": 2105, "Name": "Well 1"} |
Related
Lets say I have this Json and I would like to retrieve all the age values where the name equals Chris in the Array key.
{
"Array": [
{
"age": "65",
"name": "Chris"
},
{
"age": "20",
"name": "Mark"
},
{
"age": "23",
"name": "Chris"
}
]
}
That Json is present in the Json column inside my database.
by that I would like to retrieve one age column the has the age 65 and 23 because they both named Chris.
Use json_each() table-valued function to extract all the names and ages from the json array of each row of the table and json_extract() function to filter the rows for 'Chris' and get his age:
SELECT json_extract(j.value, '$.name') name,
json_extract(j.value, '$.age') age
FROM tablename t JOIN json_each(t.col, "$.Array") j
WHERE json_extract(j.value, '$.name') = 'Chris';
Change col to the name of the json column.
See the demo.
I have a table with two labels: id INT and value JSONB. In value I have a json object props with keys id_1, id_2, and so on, with their respective values.
Is there a way to count the rows where the JSON object props has a specific key, such as id_1?
In this example, there should be two results: rows 1 and 4.
id | value
1 | {"name": "Jhon", "props": {"id_1": {"role": "role1", "class": "class1"}, "id_2": {"role": "role2", "class": "class2"}}}
2 | {"name": "Frank", "role": ["role1", "role2"]}
3 | {"name": "Bob", "props": {"id_3": {"role": "role3", "class": "class3"}, "id_4": {"role": "role4"}}}
4 | {"name": "Carl", "props": {"id_5": {"role": "role5", "class": "class5"}, "id_1": {"class": "class6"}}}
I tried something like this, but to make it work, I have to also specify the value, but the value could change for every row. For example, with this query, I only get one row back.
SELECT count(value)
FROM "myTable"
where value->'props' ->> 'id_1' = '{"role": "role1", "class": "class1"}'
Try this-
SELECT COUNT(z.*) FROM (
SELECT id, value->'props'->>'id_1' as val FROM "myTable" ) z WHERE z.val
IS NOT NULL
Use the ? operator to test whether a key exists, regardless of value.
SELECT count(*)
FROM "myTable"
where value -> 'props' ? 'id_1
I have the json block modeled below. I want to selectively delete individual blocks from my_items based on the id which is AAA and BBB in my sample. ie if I tried to delete the AAA block under my_items I would want tojust delete the {"id" : "AAA"} but if wanted to delete the BBB block it would delete the larger {"name" : "TestRZ", "id" : "BBB", "description" : ""} block.
I know I can use the #- to remove whole blocks like SELECT '{sample_json}'::jsonb #- '{my_items}' would purge out the whole my_items block. But I dont know how to use this to conditionally delete children under a parent block of json. I have also used code similar to this example to append data inside a nested structure by reading in the node of the nested structure cat-ing new data to it and rewriting it. UPDATE data SET value= jsonb_set(value, '{my_items}', value->'items' || (:'json_to_adds'), true) where id='testnofeed'.
But I dont know how to apply either of these methods to: 1)Delete data in nested structure using #- or 2)Do the same using `jsonb_set. Anyone have any guidance for how to do this using either of these(or another method).
{
"urlName" : "testurl",
"countryside" : "",
"description" : "",
"my_items" : [
{
"id" : "AAA"
},
{
"name" : "TestRZ",
"id" : "BBB",
"description" : ""
},
],
"name" : "TheName"
}
Data is stored in value jsonb. when I update I will be able to pass in a unique kind so that it only updates this json in one row in db.
-- Table Definition
CREATE TABLE "public"."data" (
"id" varchar(100) NOT NULL,
"kind" varchar(100) NOT NULL,
"revision" int4 NOT NULL,
"value" jsonb
);
This works in PostgreSQL 12 and later with jsonpath support. If you do not have jsonpath, then please leave a comment.
with data as (
select '{
"urlName" : "testurl",
"countryside" : "",
"description" : "",
"my_items" : [
{
"id" : "AAA"
},
{
"name" : "TestRZ",
"id" : "BBB",
"description" : ""
}
],
"name" : "TheName"
}'::jsonb as stuff
)
select jsonb_set(stuff, '{my_items}',
jsonb_path_query_array(stuff->'my_items', '$ ? (#."id" <> "AAA")'))
from data;
jsonb_set
---------------------------------------------------------------------------------------------------------------------------------------------------
{"name": "TheName", "urlName": "testurl", "my_items": [{"id": "BBB", "name": "TestRZ", "description": ""}], "countryside": "", "description": ""}
(1 row)
To update the table directly, the statement would be:
update data
set value = jsonb_set(value, '{my_items}',
jsonb_path_query_array(value->'my_items',
'$ ? (#."id" <> "AAA")'));
This works for versions before PostgreSQL 12:
with data as (
select 1 as id, '{
"urlName" : "testurl",
"countryside" : "",
"description" : "",
"my_items" : [
{
"id" : "AAA"
},
{
"name" : "TestRZ",
"id" : "BBB",
"description" : ""
}
],
"name" : "TheName"
}'::jsonb as stuff
), expand as (
select d.id, d.stuff, e.item, e.rn
from data d
cross join lateral jsonb_array_elements(stuff->'my_items') with ordinality as e(item, rn)
)
select id, jsonb_set(stuff, '{my_items}', jsonb_agg(item order by rn)) as new_stuff
from expand
where item->>'id' != 'AAA'
group by id, stuff;
id | new_stuff
----+---------------------------------------------------------------------------------------------------------------------------------------------------
1 | {"name": "TheName", "urlName": "testurl", "my_items": [{"id": "BBB", "name": "TestRZ", "description": ""}], "countryside": "", "description": ""}
(1 row)
The direct update for this is a little more involved:
with expand as (
select d.id, d.value, e.item, e.rn
from data d
cross join lateral jsonb_array_elements(value->'my_items')
with ordinality as e(item, rn)
), agg as (
select id, jsonb_set(value, '{my_items}', jsonb_agg(item order by rn)) as new_value
from expand
where item->>'id' != 'AAA'
group by id, value
)
update data
set value = agg.new_value
from agg
where agg.id = data.id;
i'm create a table have one json column and data of inserted has below structure:
{
"options" : {
"info" : [
{"data" : "data1", "verified" : 0},
{"data" : "data2", "verified" : 1},
... and more
],
"otherkeys" : "some data..."
}
}
i want to run a query to get data of verified = 1 "info"
this is for mysql 5.7 comunity running on windows 10
select id, (meta->"$.options.info[*].data") AS `data`
from tbl
WHERE meta->"$.options.info[*].verified" = 1
is expect the output of "data2" but the actual output is nothing.
below query worked perfectly
select id, (meta->"$.options.info[*].data") AS `data`
from tbl
WHERE meta->"$.options.info[1].verified" = 1
but i need to search all item in array not only index 1
how can fix it ?
(sorry for bad english)
Try:
SELECT `id`, (`meta` -> '$.options.info[*].data') `data`
FROM `tbl`
WHERE JSON_CONTAINS(`meta` -> '$.options.info[*].verified', '1');
See dbfiddle.
File stored in Hive:
[
{
"occupation": "guitarist",
"fav_game": "football",
"name": "d1"
},
{
"occupation": "dancer",
"fav_game": "chess",
"name": "k1"
},
{
"occupation": "traveller",
"fav_game": "cricket",
"name": "p1"
},
{
"occupation": "drummer",
"fav_game": "archery",
"name": "d2"
},
{
"occupation": "farmer",
"fav_game": "cricket",
"name": "k2"
},
{
"occupation": "singer",
"fav_game": "football",
"name": "s1"
}
]
CSV file in hadoop:
name,age,city
d1,23,delhi
k1,23,indore
p1,23,blore
d2,25,delhi
k2,30,delhi
s1,25,delhi
I queried them individually, it's working fine. Then, I tried join query:
select * from hdfs.`/demo/distribution.csv` d join hive.demo.`user_details` u on d.name = u.name
I got the following issue:
org.apache.drill.common.exceptions.UserRemoteException: SYSTEM ERROR: DrillRuntimeException: Join only supports implicit casts between 1. Numeric data 2. Varchar, Varbinary data 3. Date, Timestamp data Left type: INT, Right type: VARCHAR. Add explicit casts to avoid this error Fragment 0:0 [Error Id: b01db9c8-fb35-4ef8-a1c0-31b68ff7ae8d on IMPETUS-DSRV03.IMPETUS.CO.IN:31010]
Please refer this https://drill.apache.org/docs/data-type-conversion/
We need to do explicit typecasting to deal with such scenario.
Consider we have a JSON file employee.json and a csv file sample.csv. In order to query on both at the same time , in one query we need to do type casting.
0: jdbc:drill:zk=local> select emp.employee_id, dept.department_description, phy.columns[2], phy.columns[3] FROM cp.`employee.json` emp , cp.`department.json` dept, dfs.`/tmp/sample.csv` phy where CAST(emp.employee_id AS INT) = CAST(phy.columns[0] AS INT) and emp.department_id = dept.department_id;
Here we are typecasting CAST(emp.employee_id AS INT) = CAST(phy.columns[0] AS INT) so that equality does not fail.
Refer this for more detail:- http://www.devinline.com/2015/11/apache-drill-setup-and-SQL-query-execution.html#multiple_src
You need to cast even though by default it has taken varchar. Try this:
select * from hdfs.`/demo/distribution.csv` d join hive.demo.`user_details` u on cast(d.name as VARCHAR) = cast(u.name as VARCHAR)
But you cannot refer to column name directly from csv. you need to consider columns[0] for name.