Return Parts of an Array in Postgres - arrays

I have a column (text) in my Postgres DB (v.10) with a JSON format.
As far as i now it's has an array format.
Here is an fiddle example: Fiddle
If table1 = persons and change_type = create then i only want to return the name and firstname concatenated as one field and clear the rest of the text.
Output should be like this:
id table1 did execution_date change_type attr context_data
1 Persons 1 2021-01-01 Create Name [["+","name","Leon Bill"]]
1 Persons 2 2021-01-01 Update Firt_name [["+","cur_nr","12345"],["+","art_cd","1"],["+","name","Leon"],["+","versand_art",null],["+","email",null],["+","firstname","Bill"],["+","code_cd",null]]
1 Users 3 2021-01-01 Create Street [["+","cur_nr","12345"],["+","art_cd","1"],["+","name","Leon"],["+","versand_art",null],["+","email",null],["+","firstname","Bill"],["+","code_cd",null]]

Disassemble json array into SETOF using json_array_elements function, then assemble it back into structure you want.
select m.*
, case
when m.table1 = 'Persons' and m.change_type = 'Create'
then (
select '[["+","name",' || to_json(string_agg(a.value->>2,' ' order by a.value->>1 desc))::text || ']]'
from json_array_elements(m.context_data::json) a
where a.value->>1 in ('name','firstname')
)
else m.context_data
end as context_data
from mutations m
modified fiddle
(Note:
utilization of alphabetical ordering of names of required fields is little bit dirty, explicit order by case could improve readability
resulting json is assembled from string literals as much as possible since you didn't specified if "+" should be taken from any of original array elements
the to_json()::text is just for safety against injection
)

Related

SQL Server: How to remove a key from a Json object

I have a query like (simplified):
SELECT
JSON_QUERY(r.SerializedData, '$.Values') AS [Values]
FROM
<TABLE> r
WHERE ...
The result is like this:
{ "2019":120, "20191":120, "201902":121, "201903":134, "201904":513 }
How can I remove the entries with a key length less then 6.
Result:
{ "201902":121, "201903":134, "201904":513 }
One possible solution is to parse the JSON and generate it again using string manipulations for keys with desired length:
Table:
CREATE TABLE Data (SerializedData nvarchar(max))
INSERT INTO Data (SerializedData)
VALUES (N'{"Values": { "2019":120, "20191":120, "201902":121, "201903":134, "201904":513 }}')
Statement (for SQL Server 2017+):
UPDATE Data
SET SerializedData = JSON_MODIFY(
SerializedData,
'$.Values',
JSON_QUERY(
(
SELECT CONCAT('{', STRING_AGG(CONCAT('"', [key] ,'":', [value]), ','), '}')
FROM OPENJSON(SerializedData, '$.Values') j
WHERE LEN([key]) >= 6
)
)
)
SELECT JSON_QUERY(d.SerializedData, '$.Values') AS [Values]
FROM Data d
Result:
Values
{"201902":121,"201903":134,"201904":513}
Notes:
It's important to note, that JSON_MODIFY() in lax mode deletes the specified key if the new value is NULL and the path points to a JSON object. But, in this specific case (JSON object with variable key names), I prefer the above solution.

Adding multiple records from a string

I have a string of email addresses. For example, "a#a.com; b#a.com; c#a.com"
My database is:
record | flag1 | flag2 | emailaddresss
--------------------------------------------------------
1 | 0 | 0 | a#a.com
2 | 0 | 0 | b#a.com
3 | 0 | 0 | c#a.com
What I need to do is parse the string, and if the address is not in the database, add it.
Then, return a string of just the record numbers that correspond to the email addresses.
So, if the call is made with "A#a.com; c#a.com; d#a.com", the rountine would add "d#a.com", then return "1, 3,4" corresponding to the records that match the email addresses.
What I am doing now is calling the database once per email address to look it up and confirm it exists (adding if it doesn't exist), then looping thru them again to get the addresses 1 by 1 from my powershell app to collect the record numbers.
There has to be a way to just pass all of the addresses to SQL at the same time, right?
I have it working in powershell.. but slowly..
I'd love a response from SQL as shown above of just the record number for each email address in a single response. That is, "1,2,4" etc.
My powershell code is:
$EmailList2 = $EmailList.split(";")
# lets get the ID # for each eamil address.
foreach($x in $EmailList2)
{
$data = exec-query "select Record from emailaddresses where emailAddress = #email" -parameter #{email=$x.trim()} -conn $connection
if ($($data.Tables.record) -gt 0)
{
$ResponseNumbers = $ResponseNumbers + "$($data.Tables.record), "
}
}
$ResponseNumbers = $($ResponseNumbers+"XX").replace(", XX","")
return $ResponseNumbers
You'd have to do this in 2 steps. Firstly INSERT the new values and then use a SELECT to get the values back. This answer uses delimitedsplit8k (not delimitedsplit8k_LEAD) as you're still using SQL Server 2008. On the note of 2008 I strongly suggest looking at upgrade paths soon as you have about 6 weeks of support left.
You can use the function to split the values and then INSERT/SELECT appropriately:
DECLARE #Emails varchar(8000) = 'a#a.com;b#a.com;c#a.com';
WITH Emails AS(
SELECT DS.Item AS Email
FROM dbo.DelimitedSplit8K(#Emails,';') DS)
INSERT INTO YT (emailaddress) --I don't know what the other columns value should be, so have excluded
SELECT E.Email
FROM dbo.YourTable YT
LEFT JOIN Emails E ON YT.emailaddress = E.Email
WHERE E.Email IS NULL;
SELECT YT.record
FROM dbo.YourTable YT
JOIN dbo.DelimitedSplit8K(#Emails,';') DS ON DS.Item = YT.emailaddress;

Filter SQL datatable according to different parameters, without a WHERE clause

I'm building an application that needs to allow the user to filter a data table according to different filters. So, the user will have three different filter posibilites but he might use only one, or two or the three of them at the same tame.
So, let's say I have the following columns on the table:
ID (int) PK
Sede (int)
Programa (int)
Estado (int)
All of those columns will store numbers, integers. The "ID" column is the primary key, "Sede" stores 1 or 2, "Programa" is any number between 1 and 15, and "Estado" will store numbers between 1 and 13.
The user may filter the data stored in the table using any of those filters (Sede, Programa or Estado). But the might, as well, use two filters, or the three of them at the same time.
The idea is that this application works like the data filters on Excel. I created a simulated table on excel to show what I want to achieve:
This first image shows the whole table, without applying any filter.
Here, the user selected a filter for "Sede" and "Programa" but leaved the "Estado" filter empty. So the query returns the values that are equal to the filter, but leaves the "Estado" filter open, and brings all the records, filering only by "Sede" (1) and "Programa" (6).
In this image, the user only selected the "Estado" filter (5), so it brings all the records that match this criteria, it doesn't matter if "Sede" or "Programa" are empty.
If I use a SELECT clasuse with a WHERE on it, it will work, but only if the three filters have a value:
DECLARE #sede int
DECLARE #programa int
DECLARE #estado int
SET #sede = '1'
SET #programa = '5'
SET #estado = '12'
SELECT * FROM [dbo].[Inscripciones]
WHERE
([dbo].[Inscripciones].[Sede] = #sede)
AND
([dbo].[Inscripciones].[Programa] = #programa)
AND
([dbo].[Inscripciones].[Estado] = #estado)
I also tryed changing the "AND" for a "OR", but I can't get the desired result.
Any help will be highly appreciated!! Thanks!
common problem: try using coalesce on the variable and for the 2nd value use the field name you're comparing to. Be careful though; Ensure it's NULL and not empty string being passed!
What this does is take the first non-null value of the variable passed in or the value you're comparing to.. Thus if the value passed in is null the comparison will always return true.
WHERE
[dbo].[Inscripciones].[Sede] = coalesce(#sede, [dbo].[Inscripciones].[Sede])
AND
[dbo].[Inscripciones].[Programa] = coalesce(#programa, [dbo].[Inscripciones].[Programa])
AND
[dbo].[Inscripciones].[Estado] = coalesce(#estado, [dbo].[Inscripciones].[Estado])
If sede is null and programa and estado are populated the compare would look like...
?=? (or 1=1)
?=programa variable passed in
?=Estado variable passed in
Boa Sorte!
Thank you all for your anwers. After reading the article posted in the comments by #SeanLange I was finally able to achieve what was needed. Using a CASE clause in the WHERE statement solves the deal. Here's the code:
SELECT
*
FROM [dbo].[Inscripciones]
WHERE
([dbo].[Inscripciones].[Sede] = (CASE WHEN #sede = '' THEN [dbo].[Inscripciones].[Sede] ELSE #sede END))
AND
([dbo].[Inscripciones].[Programa] = (CASE WHEN #programa = '' THEN [dbo].[Inscripciones].[Programa] ELSE #programa END))
AND
([dbo].[Inscripciones].[Estado] = (CASE WHEN #estado = '' THEN [dbo].[Inscripciones].[Estado] ELSE #estado END))
AND
([dbo].[Inscripciones].[TipoIngreso] = (CASE WHEN #tipoingreso = '' THEN [dbo].[Inscripciones].[TipoIngreso] ELSE #tipoingreso END))
Thanks again!!

Update query failed '0' rows affected

I am trying to run this query but the query keeps giving up on me:
Update StockInvoiceInfo set Quantity = Quantity - 2 where p_id = 5 AND ProductDate = convert(Cast('31-5-2015' as datetime)) ;
After Running this code it returns an error below:
Incorrect syntax near '31-5-2015'
The datatype of the ProductDate column isDate. I am using Sql Server 2012.
You have used Convert functions but didn't supplied it with parameters. Also there is no need for this function here. Also take care of date format. I have changed it to standard format:
Update StockInvoiceInfo set Quantity = Quantity - 2
where p_id = 5 AND ProductDate = Cast('2015-05-31' as datetime)
If all you are trying to do is compare a Sql Date, then just use an agnostic format like '20150531' or easier to read '2015-05-31'. No need for casts or convert at all, i.e.
WHERE ... AND ProductDate = '2015-05-31'
However, if ProductDate isn't a date, but one of the *DATETIME* data types, and you are looking to update any time on the same day, then I believe you are looking for something like:
Update StockInvoiceInfo
set Quantity = Quantity - 2
where
p_id = 5
AND CAST(ProductDate AS DATE) = '2015-05-31';
However, the performance will be lousy as the clause isn't likely to be SARGable. You're better off simply doing:
AND ProductDate >= '2015-05-31' AND ProductDate < '2015-06-01';
(Resist the temptation to use between, or hacks like ':23:59:59' as there will be data corner cases which will bite you)
use CAST('5-31-2015' as DATETIME)
with the above update statement you started convert but with incomplete syntax
here the convert syntax
Update StockInvoiceInfo
set Quantity = Quantity - 2
where p_id = 5
AND ProductDate = convert(datetime,Cast('31-5-2015' as varchar),103) ;

Removing the repeating elements from a row in a squlite table

Please let me know if there is any query where in I remove the repeating entries in a row.
For eg: I have a table which has name with 9 telephone numbers:
Name Tel0 Tel1 Tel2 Tel3 Tel4 Tel5 Tel6 Tel7 Tel8
John 1 2 2 2 3 3 4 5 1
The final result should be as shown below:
Name Tel0 Tel1 Tel2 Tel3 Tel4 Tel5 Tel6 Tel7 Tel8
John 1 2 3 4 5
regards
Maddy
I fear that it will be more complicated to keep this format than to split the table in two as I suggested. If you insist on keeping the current schema then I would suggest that you query the row, organise the fields in application code and then perform an update on the database.
You could also try to use SQL UNION operator to give you a list of the numbers, a UNION by default will remove all duplicate rows:
SELECT Name, Tel FROM
(SELECT Name, Tel0 AS Tel FROM Person UNION
SELECT Name, Tel1 FROM Person UNION
SELECT Name, Tel2 FROM Person) ORDER BY Name ;
Which should give you a result set like this:
John|1
John|2
You will then have to step through the result set and saving each number into a separate variable (skipping those variables that do not exist) until the "Name" field changes.
Tel1 := Null; Tel2 := Null;
Name := ResultSet['Name'];
Tel0 := ResultSet['Tel'];
ResultSet.Next();
if (Name == ResultSet['Name']) {
Tel1 := ResultSet['Tel'];
} else {
UPDATE here.
StartAgain;
}
ResultSet.Next();
if (Name == ResultSet['Name']) {
Tel2 := ResultSet['Tel'];
} else {
UPDATE here.
StartAgain;
}
I am not recommending you do this, it is very bad use of a relational database but once implemented in a real language and debugged that should work.

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