I have column that is returning from my query that is an array of array. It looks like this.
array_vals: {{NULL,NULL,147.89,87.27,82.65,83.41,93.69,101.90,NULL,NULL}}
When I try to query in to my array first array I always get Null values.
select array_vals[0] from table
This returns null. But my desired results would be {NULL,NULL,147.89,87.27,82.65,83.41,93.69,101.90,NULL,NULL}
with test as (
select 1 as value, array_agg(array[1 , 3, 4]) as data
group by value
)
select data[1] from test
This returns null for me.
Related
I have three array columns in a postgres table.
column array_a has values like {"red","blue","green"}
column array_b has values like {"blue","green"}
I would like to update column array_c to the array from array_a with any value found in array_b removed
so in this case array_c would be {"red"}
update my_table
set array_c = (
array_remove(array_a, UNNEST(array_b)));
works except that if array_b is Null everything is removed.
I can fix that by separating out the query into
WHERE array_b IS NOT NULL
and
WHERE array_b IS NULL
but is there a way to catch the null problem within the original query?
Our system uses postgres for its database.
We have queries that can select rows from a database table where an array field in the table contains a specific value, e.g.:
Find which employee manages the employee with ID 123.
staff_managed_ids is a postgres array field containing an array of the employees that THIS employee manages.
This query works as expected:
select *
from employees
where 123=any(staff_managed_ids)
We now need to query where an array field contains a postgres NULL. We tried the following query, but it doesn't work:
select *
from employees
where NULL=any(staff_managed_ids)
We know the staff_managed_ids array field contains NULLs from other queries.
Are we using NULL wrongly?
NULL can not be compared using =. The only operators that work with that are IS NULL and IS NOT NULL.
To check for nulls, you need to unnest the elements:
select e.*
from employees e
where exists (select *
from unnest(e.staff_managed_ids) as x(staff_id)
where x.staff_id is null);
if all your id values are positive, you could write something like this:
select *
from employees
where (-1 < all(staff_managed_ids)) is null;
how this works is that -1 should be less than all values, however comparison with null will make the whole array comparison expression null.
I have column options with type jsonb , in format {"names": ["name1", "name2"]} which was created with
UPDATE table1 t1 SET options = (SELECT jsonb_build_object('names', names) FROM table2 t2 WHERE t2.id= t1.id)
and where names have type jsonb array.
SELECT jsonb_typeof(names) FROM table2 give array
Now I want to extract value of names as jsonb array. But query
SELECT jsonb_build_array(options->>'names') FROM table
gave me ["[\"name1\", \"name2\"]"], while I expect ["name1", "name2"]
How can I get value in right format?
The ->> operator will return the value of the field (in your case, a JSON array) as a properly escaped text. What you are looking for is the -> operator instead.
However, note that using the jsonb_build_array on that will return an array containing your original array, which is probably not what you want either; simply using options->'names' should get you what you want.
Actually, you don't need to use jsonb_build_array() function.
Use select options -> 'names' from table; This will fix your issue.
jsonb_build_array() is for generating the array from jsonb object. You are following wrong way. That's why you are getting string like this ["[\"name1\", \"name2\"]"].
Try to execute this sample SQL script:
select j->'names'
from (
select '{"names": ["name1", "name2"]}'::JSONB as j
) as a;
I've got a column in a table that's a json. It contains only values without keys like
Now I'm trying to split the data from the json and create new table using every index of each array as new entry like
I've already tried
SELECT JSON_QUERY(abc) as 'Type', Id as 'ValueId' from Table FOR JSON AUTO
Is there any way to handle splitting given that some arrays might be empty and look like
[]
?
A fairly simply approach would be to use outer apply with openjson.
First, create and populate sample table (Please save us this step in your future questions):
DECLARE #T AS TABLE
(
Id int,
Value nvarchar(20)
)
INSERT INTO #T VALUES
(1, '[10]'),
(2, '[20, 200]'),
(3, '[]'),
(4, '')
The query:
SELECT Id, JsonValues.Value
FROM #T As t
OUTER APPLY
OPENJSON( Value ) As JsonValues
WHERE ISJSON(t.Value) = 1
Results:
Id Value
1 10
2 20
2 200
3 NULL
Note the ISJSON condition in the where clause will prevent exceptions in case the Value column contains anything other than a valid json (an empty array [] is still considered valid for this purpose).
If you don't want to return a row where the json array is empty, use cross apply instead of outer apply.
Your own code calling for FOR JSON AUTO tries to create JSON out of tabular data. But what you really needs seems to be the opposite direction: You want to transform JSON to a result set, a derived table. This is done by OPENJSON.
Your JSON seems to be a very minimalistic array.
You can try something along this.
DECLARE #json NVARCHAR(MAX) =N'[1,2,3]';
SELECT * FROM OPENJSON(#json);
The result returns the zero-based ordinal position in key, the actual value in value and a (very limited) type-enum.
Hint: If you want to use this against a table's column you must use APPLY, something along
SELECT *
FROM YourTable t
OUTER APPLY OPENJSON(t.TheJsonColumn);
I'm using the following query to sum the entire column. In the TOREMOVEALLPRIV column, I have both integer and null values.
I want to sum both null and integer values and print the total sum value.
Here is my query which print the sum values as null:
select
sum(URT.PRODSYS) as URT_SUM_PRODSYS,
sum(URT.Users) as URT_SUM_USERS,
sum(URT.total_orphaned) as URT_SUM_TOTAL_ORPHANED,
sum(URT.Bp_errors) as URT_SUM_BP_ERRORS,
sum(URT.Ma_errors) as URT_SUM_MA_ERRORS,
sum(URT.Pp_errors) as URT_SUM_PP_ERRORS,
sum(URT.REQUIREURTCBN) as URT_SUM_CBNREQ,
sum(URT.REQUIREURTQEV) as URT_SUM_QEVREQ,
sum(URT.REQUIREURTPRIV) as URT_SUM_PRIVREQ,
sum(URT.cbnperf) as URT_SUM_CBNPERF,
sum(URT.qevperf) as URT_SUM_QEVPERF,
sum(URT.privperf) as URT_SUM_PRIVPERF,
sum(URT.TO_REMOVEALLPRIV) as TO_REMOVEALLPRIV_SUM
from
URTCUSTSTATUS URT
inner join CUSTOMER C on URT.customer_id=C.customer_id;
Output image:
Expected Output:
Instead of null, I need to print sum of rows whichever have integers.
The SUM function automatically handles that for you. You said the column had a mix of NULL and numbers; the SUM automatically ignores the NULL values and correctly returns the sum of the numbers. You can read it on IBM Knowledge Center:
The function is applied to the set of values derived from the argument values by the elimination of null values.
Note: All aggregate functions ignore NULL values except the COUNT function. Example: if you have two records with values 5 and NULL, the SUM and AVG functions will both return 5, but the COUNT function will return 2.
However, it seems that you misunderstood why you're getting NULL as a result. It's not because the column contains null values, it's because there are no records selected. That's the only case when the SUM function returns NULL. If you want to return zero in this case, you can use the COALESCE or IFNULL function. Both are the same for this scenario:
COALESCE(sum(URT.TO_REMOVEALLPRIV), 0) as TO_REMOVEALLPRIV_SUM
or
IFNULL(sum(URT.TO_REMOVEALLPRIV), 0) as TO_REMOVEALLPRIV_SUM
I'm guessing that you want to do the same to all other columns in your query, so I'm not sure why you only complained about the TO_REMOVEALLPRIV column.
What you're looking for is the COALESCE function:
select
sum(URT.PRODSYS) as URT_SUM_PRODSYS,
sum(URT.Users) as URT_SUM_USERS,
sum(URT.total_orphaned) as URT_SUM_TOTAL_ORPHANED,
sum(URT.Bp_errors) as URT_SUM_BP_ERRORS,
sum(URT.Ma_errors) as URT_SUM_MA_ERRORS,
sum(URT.Pp_errors) as URT_SUM_PP_ERRORS,
sum(URT.REQUIREURTCBN) as URT_SUM_CBNREQ,
sum(URT.REQUIREURTQEV) as URT_SUM_QEVREQ,
sum(URT.REQUIREURTPRIV) as URT_SUM_PRIVREQ,
sum(URT.cbnperf) as URT_SUM_CBNPERF,
sum(URT.qevperf) as URT_SUM_QEVPERF,
sum(URT.privperf) as URT_SUM_PRIVPERF,
sum(COALESCE(URT.TO_REMOVEALLPRIV,0)) as TO_REMOVEALLPRIV_SUM
from
URTCUSTSTATUS URT
inner join CUSTOMER C on URT.customer_id=C.customer_id;