I was trying to convert the below query to sqlalchemy:
SELECT
addr_idn,
(SELECT MAX(LastUpdateDate)
FROM (VALUES (crt_dt),(upd_dt)) AS UpdateDate(LastUpdateDate))
AS LastUpdateDate
FROM (
select a. addr_idn,a.crt_dt crt_dt , b.upd_dt upd_dt
from emp_addr
where emp_addr.addr_idn = 1
) a
but I am not able to convert this into sqlalchemy. Please help me out to convert this query.
Credit To : Mike Bayer
The hard part here is the "FROM VALUES" which is not built-in to
SQLAlchemy.
There is a recipe at
https://bitbucket.org/zzzeek/sqlalchemy/wiki/UsageRecipes/PGValues
that will show how to build a "values()" function that will give you
the VALUES() expression you're looking for.
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and
Verifiable Example. See http://stackoverflow.com/help/mcve for a full
description.
Related
I am trying to flatten an array using UNNEST function in the Table API.
Am I doing something wrong or it is not a supported function ? This page suggests it though: https://ci.apache.org/projects/flink/flink-docs-master/dev/table/sql/queries.html
Thanks !
Code
Python udf
#udf(input_types=DataTypes.STRING(), result_type=DataTypes.ARRAY(DataTypes.STRING()))
def explode(s):
return 3*[s]
t_env.register_function("explode", explode)
Processing
tab = t_env.from_path('mySource').select("id, explode(dummy) as dummy_list")
t_env.register_table("temp_table", tab)
t_env.sql_query("SELECT t.item as dummy_item FROM UNNEST(select dummy_list from temp_table) AS t(item)").insert_into("mySink")
Execution
t_env.execute("dummy_unnest")
Error
TableException: Cannot generate a valid execution plan for the given query:
LogicalProject(dummy_item=[$0])
Uncollect
LogicalProject(EXPR$0=[org$apache$flink$table$functions$python$PythonScalarFunction$908596b4671476ee325743dba92ed6c7($1)])
LogicalTableScan(table=[[default_catalog, default_database, mySource]])
This exception indicates that the query uses an unsupported SQL feature.
Please check the documentation for the set of currently supported SQL features.
I think you can change the query to
select id, dummy_item from temp_table CROSS JOIN UNNEST(dummy_list) AS t (dummy_item)
If it's relevant I'm using Django with Django Rest Framework, django-mssql-backend and pyodbc
I am building some read only models of a legacy database using fairly complex queries and Django's MyModel.objects.raw() functionality. Initially I was executing the query as a Select query which was working well, however I received a request to try and do the same thing but with a table-valued function from within the database.
Executing this:
MyModel.objects.raw(select * from dbo.f_mytablefunction)
Gives the error: Invalid object name 'myapp_mymodel'.
Looking deeper into the local variables at time of error it looks like this SQL is generated:
'SELECT [myapp_mymodel].[Field1], '
'[myapp_mymodel].[Field2] FROM '
'[myapp_mymodel] WHERE '
'[myapp_mymodel].[Field1] = %s'
The model itself is mapped properly to the query as executing the equivalent:
MyModel.objects.raw(select * from dbo.mytable)
Returns data as expected, and dbo.f_mytablefunction is defined as:
CREATE FUNCTION dbo.f_mytablefunction
(
#param1 = NULL etc etc
)
RETURNS TABLE
AS
RETURN
(
SELECT
field1, field2 etc etc
FROM
dbo.mytable
)
If anyone has any explanation as to why these two modes of operation are treated substantially differently then I would be very pleased to find out.
Guess you've figured this out by now (see docs):
MyModel.objects.raw('select * from dbo.f_mytablefunction(%s)', [1])
If you'd like to map your table valued function to a model, this gist has a quite thorough approach, though no license is mentioned.
Once you've pointed your model 'objects' to the new TableFunctionManager and added the 'function_args' OrderedDict (see tests in gist), you can query it as follows:
MyModel.objects.all().table_function(param1=1)
For anyone wondering about use cases for table valued functions, try searching for 'your_db_vendor tvf'.
I need to make hierarchical queries, and I need to get the results of CONNECT_BY_ISCYCLE and CONNECT_BY_ISLEAF, but these features are supported in Oracle not in Snowflake.
What are the alternative ways to implement the functionalities of CONNECT_BY_ISCYCLE and CONNECT_BY_ISLEAF in snowflake without using them as these keywords are not supported there?
Wonder if you have taken a look at the following Snowflake features?
https://docs.snowflake.net/manuals/user-guide/queries-hierarchical.html#using-connect-by-or-recursive-ctes-to-query-hierarchical-data
Yes I took a look there. I also took a look at https://docs.snowflake.net/manuals/sql-reference/constructs/connect-by.html where it clearly says that these features are not supported in Snowflake.
I was trying below code block to find an alternative but facing varieties of error in snowflake.
person_vertex as (
select
emp_number,
user_id
from person
),
person_edges as (
select
supervisor_emp_number,
emp_number
from person
where supervisor_emp_number is not null
),
select
pv.emp_number emp_id_pk,
level,
CONNECT_BY_ROOT pv.emp_number AS root,
concat(SYS_CONNECT_BY_PATH(pv.emp_number,':'),':') as path,
-- CONNECT_BY_ISCYCLE AS iscyclic, ------------------- no idea how to implement this
-- CONNECT_BY_ISLEAF as isleaf ------------------- i tried below block, but it is not working
case
when (pe.supervisor_emp_number in (select emp_number from pv)) then 0
else 1
end AS isleaf
from person_vertex pv
left join person_edges pe on pv.emp_number = pe.emp_number
connect by prior A.emp_number = A.supervisor_emp_number
start with A.supervisor_emp_number is null
Any help with this block is really appreciated.
Thanks.
enter code here
I have created an Sql table to trace objects' operation history. I have two columns; first one is the self tracing code and second tracing code is the tracing code for the code coming from source object to target. I created this to be able to look up the route of operations through the objects. You can see the tracing sample table below:
I need to create an sql code to query to show all the route in one table. When I first select the self code, it will be the incoming code for previous rows. There may be more than one incoming code to self and I want to be able to trace all. And I want to reach end until my search is null.
I tried select query like below but I am so new sql and need your help.
SELECT [TracingCode.Self],
[TracingCode.Incoming],
[EquipmentNo]
FROM [MKP_PROCESS_PRODUCT_REPORTS].[dbo].[ProductionTracing.Main]
WHERE [TracingCode.Self] = (SELECT [TracingCode.Incoming]
FROM [MKP_PROCESS_PRODUCT_REPORTS].[dbo].[ProductionTracing.Main]
WHERE [TracingCode.Self] = (SELECT [TracingCode.Incoming]
FROM [MKP_PROCESS_PRODUCT_REPORTS].[dbo].[ProductionTracing.Main]
WHERE [TracingCode.Self] = (SELECT [TracingCode.Incoming]
FROM [MKP_PROCESS_PRODUCT_REPORTS].[dbo].[ProductionTracing.Main]
WHERE [TracingCode.Self] = '028.001.19.2.3')));
To do this kind of parent/child thing to any level without explicitly coding all levels you need to use a recursive CTE.
More details here
https://www.red-gate.com/simple-talk/sql/t-sql-programming/sql-server-cte-basics/
Here is some test data and a solution I came up with. Note that three records actually match 028.001.19.2.3
If this doesn't do what you need please explain further with sample data.
DECLARE #Sample TABLE (
TC_Self CHAR(14) NOT NULL,
TC_In CHAR(14) NOT NULL,
EquipmentNo INT NOT NULL
);
INSERT INTO #Sample (TC_Self, TC_In, EquipmentNo)
VALUES
('028.001.19.2.3','026.003.19.2.2',96),
('028.001.19.2.3','026.001.19.2.2',96),
('028.001.19.2.3','026.002.19.2.2',96),
('028.001.19.2.2','026.002.19.2.1',96),
('028.001.19.2.2','026.002.19.2.1',96),
('028.001.19.2.1','026.002.19.1.1',96),
('026.003.19.2.2','024.501.19.2.5',117),
('024.501.19.2.5','024.501.19.2.6',999),
('024.501.19.2.6','024.501.19.2.7',998);
WITH CTE (RecordType, TC_Self, TC_In, EquipmentNo)
AS
(
-- This is the 'root'
SELECT 'Root' RecordType, TC_Self, TC_In, EquipmentNo FROM #Sample
WHERE TC_Self = '028.001.19.2.3'
UNION ALL
SELECT 'Leaf' RecordType, S.TC_Self, S.TC_In, S.EquipmentNo FROM #Sample S
INNER JOIN CTE
ON S.TC_Self = CTE.TC_In
)
SELECT * FROM CTE;
Also please note that most of the time to generate this answer was taken in generating the sample data to use.
In future when asking questions, people are far more likely to help if you post this sample data generation yourself
HANA Version: SP12
All,
I've successfully created Calc Views with INPUT_PARAMETERS as described by Lars in many blogs and forums. While these views work without issue when querying directly for single and multi inputs, I'm encountering an issue with performing joins on the Calc View itself within a stored proc or table function.
Example:
"BASE_SCHEMA"."BASE_TABLE_EXAMPLE" - record count(*) ~ 2million records
Keys: Material (20k distinct), Plant (200 distinct)
"_SYS_BIC"."CA_EXAMPLE_PRODUCTIVITY"
Input Parameters: IP_MATNR (nvarchar (5000)), IP_PLANT (nvarchar(5000))
Issue #1: The maximum value for nvarchar is 5000. Unable to utilize multiple inputs within the parameter if the count of distinct characters are 5000+.
Issue #2: How to use PLACEHOLDER logic in the same method of performing an INNER_JOIN in SQL.
base_data =
select
PLANT
,MATERIAL
from "BASE_SCHEMA"."BASE_TABLE_EXAMPLE"
group by PLANT,MATERIAL;
I would think to perform the below but the output would cause issues when concatenating multiple strings for use within input parameter of nvarchar(5000).
select
string_agg(PLANT,''',''') as PLANT
,string_agg(MATERIAL,''',''') as MATERIAL
into var_PLANT, var_MATERIAL
from
(
select
PLANT
,MATERIAL
from :base_data
);
While I'm successful up to this point, once adding the variables into the PLACEHOLDER of the Calc View, it fails stating that I'm passing too many characters to the IP. Any suggestions??? Thanks in advance.
base_calc =
select
PLANT
,MATERIAL
,MATERIAL_BU
,etc....
from "_SYS_BIC"."CA_EXAMPLE_PRODUCTIVITY"
(PLACEHOLDER."IP_MATNR"=> :var_MATERIAL, --<---Fails here. :(
PLACEHOLDER."IP_PLANT"=> :var_PLANT);
Question raised on SAP SCN. Located here!
Did you tried to use WHERE clause instead of PLACEHOLDER?
base_calc =
select
PLANT,
MATERIAL,
MATERIAL_BU,
etc....
from "_SYS_BIC"."CA_EXAMPLE_PRODUCTIVITY"
WHERE MATERIAL = var_MATERIAL AND PLANT = var_PLANT;