I have a JSON column and the data stored looks like:
{"results":{"made":true,"cooked":true,"eaten":true}}
{"results":{"made":true,"cooked":true,"eaten":false}}
{"results":{"made":true,"eaten":true,"a":false,"b":true,"c":false}, "more": {"ignore":true}}
I need to find all rows where 1+ values in $.results is false.
I tried using JSON_CONTAINS() but didn't find a way to get it to compare to a boolean JSON value, or to look at all values in $.results.
This needs to work with MySQL 5.7 but if it's not possible I will accept a MySQL 8+ answer.
I don't know the way for to search for a JSON true/false/null value using JSON functions - in practice these values are treated as string-type values during the search with JSON_CONTAINS, JSON_SEARCH, etc.
Use regular expression for the checking. Something like
SELECT id,
JSON_PRETTY(jsondata)
FROM test
WHERE jsondata REGEXP '"results": {[^}]+: false.*}';
DEMO
You could simply search the JSON_EXTRACT using the LIKE condition this way.
SELECT * FROM table1 WHERE JSON_EXTRACT(json_dict, '$.results') LIKE '%: false%';
Check this DB FIDDLE
An alternative to the pattern matching in other answers, is to extract all values from $.results and check each entry with a helper table with running numbers
SELECT DISTINCT v.id, v.json_value
FROM (
SELECT id, json_value, JSON_EXTRACT(json_value, '$.results.*') value_array
FROM json_table
) v
JOIN seq ON seq.n < JSON_LENGTH(v.value_array)
WHERE JSON_EXTRACT(v.value_array, CONCAT('$[', seq.n, ']')) = false
Here is the demo
Related
I have the following table:
I need to create a select that returns me something like this:
I have tried this code:
SELECT Code, json_extract_path(Registers::json,'sales', 'name')
FROM tbl_registers
The previous code returns me a NULL in json_extract_path, I have tried the operator ::json->'sales'->>'name', but doesn't work too.
You need to unnest the array, and the aggregate the names back. This can be done using json_array_elements with a scalar sub-query:
select code,
(select string_agg(e ->> 'name', ',')
from json_array_elements(t.products) as x(e)) as products
from tbl_registers t;
I would also strongly recommend to change your column's type to jsonb
step-by-step demo:db<>fiddle
SELECT
code,
string_agg( -- 3
elems ->> 'name', -- 2
','
) as products
FROM tbl_registers,
json_array_elements(products::json) as elems -- 1
GROUP BY code
If you have type text (strictly not recommended, please use appropriate data type json or jsonb), then you need to cast it into type json (I guess you have type text because you do the cast already in your example code). Afterwards you need to extract the array elements into one row per element
Fetch the name value
Reaggregate by grouping and use string_agg() to create the string list
In a word, I want to
select * from test.population where Number in (1,2,3),
but in the place of (1,2,3) I want to have a function that returns json array. So that I want to have this to be working like this.
select * from test.population where Number in ('[1,2,3]')
How to put json-array into where it clause?
You can use the MEMBER OF operator:
Number member of ('[1,2,3]')
You can use JSON_SEARCH(). It is available since MySQL 5.7, whereas MEMBER OF() came with MySQL 8.0:
select * from test.population where json_search('[1,2,3]', 'one', number) is not null
I’m trying to make the following sql statement in a json file:
SELECT user_id
FROM users_to_users
WHERE (user_id, contact_user_id, contact_blocked) IN ?
I tried providing an array of arrays for the ? Values but that returned an error. Is there a way with json to pass an array of tuples for the inserts in the above sql statement?
Simple Example:-
Use the FIND_IN_SET function:
SELECT t.*
FROM YOUR_TABLE t
WHERE FIND_IN_SET(3, t.ids) > 0
-- all books with tags starting 'Java':
SELECT * FROM `book`
WHERE JSON_SEARCH(tags, 'one', 'Java%') IS NOT NULL;
Check This Reference which uses JSON To see the whole possible Solutions
Reference Of FIND_IN_SET Answer
Given a table that contains a column of JSON like this:
{"payload":[{"type":"b","value":"9"}, {"type":"a","value":"8"}]}
{"payload":[{"type":"c","value":"7"}, {"type":"b","value":"3"}]}
How can I write a Presto query to give me the average b value across all entries?
So far I think I need to use something like Hive's lateral view explode, whose equivalent is cross join unnest in Presto.
But I'm stuck on how to write the Presto query for cross join unnest.
How can I use cross join unnest to expand all array elements and select them?
Here's an example of that
with example(message) as (
VALUES
(json '{"payload":[{"type":"b","value":"9"},{"type":"a","value":"8"}]}'),
(json '{"payload":[{"type":"c","value":"7"}, {"type":"b","value":"3"}]}')
)
SELECT
n.type,
avg(n.value)
FROM example
CROSS JOIN
UNNEST(
CAST(
JSON_EXTRACT(message,'$.payload')
as ARRAY(ROW(type VARCHAR, value INTEGER))
)
) as x(n)
WHERE n.type = 'b'
GROUP BY n.type
with defines a common table expression (CTE) named example with a column aliased as message
VALUES returns a verbatim table rowset
UNNEST is taking an array within a column of a single row and returning the elements of the array as multiple rows.
CAST is changing the JSON type into an ARRAY type that is required for UNNEST. It could easily have been an ARRAY<MAP< but I find ARRAY(ROW( nicer as you can specify column names, and use dot notation in the select clause.
JSON_EXTRACT is using a jsonPath expression to return the array value of the payload key
avg() and group by should be familiar SQL.
As you pointed out, this was finally implemented in Presto 0.79. :)
Here is an example of the syntax for the cast from here:
select cast(cast ('[1,2,3]' as json) as array<bigint>);
Special word of advice, there is no 'string' type in Presto like there is in Hive.
That means if your array contains strings make sure you use type 'varchar' otherwise you get an error msg saying 'type array does not exist' which can be misleading.
select cast(cast ('["1","2","3"]' as json) as array<varchar>);
The problem was that I was running an old version of Presto.
unnest was added in version 0.79
https://github.com/facebook/presto/blob/50081273a9e8c4d7b9d851425211c71bfaf8a34e/presto-docs/src/main/sphinx/release/release-0.79.rst
This is the query i'm trying to run:
UPDATE files set refcount=
(
SELECT count(*)
FROM comments WHERE data=files.id
)
WHERE id=?;
The problem is, comments.data is a text column (for other reasons). So I need to cast files.id as a STRING instead of what it is (an INT), because otherwise the comments.data index won't be used.
For example, this query runs fine:
SELECT count(*) FROM comments WHERE data='1234';
But this one takes forever (because it cannot use the index, comments has 10M rows):
SELECT count(*) FROM comments WHERE data=1234;
Perhaps I need to use #vars or something? I tried putting the thing in quotes, but that uses the literal "files.id" i think.
UPDATE files set refcount=
(
SELECT count(*)
FROM comments WHERE data='files.id'
)
WHERE id=?;
All you have to do is to cast files.id into string before comparing it to data
something like this :
UPDATE files set refcount=
(
SELECT count(*)
FROM comments WHERE data=CAST(files.id AS vachar)
)
WHERE id=?;
Here's a link that show how you can use cast functions and operators in mysql.
UPDATED: It seems that for some reasons CAST is not working with varchar.Though char might do the trick (whih in case it doesn't as Timh said in the comments below) CONCAT can be used to convert other types to a varchar (when you concat othery types with a string it returns a string and concating with an empty string will act as some sort of conversion :) )