In Legacy sql, we can do SELECT ABS(HASH('12345')) to get unique hash number of a value.
I am in process of converting legacy sql to standard sql in GBQ,
so wondering whats the best way to convert above function so that it gives me same value back as legacy sql.
We won't expose a function that returns the same values as in legacy SQL; it uses an undocumented implementation. The closest equivalent when using standard SQL is FARM_FINGERPRINT, which uses the open-source FarmHash library.
For the expression that you provided, you would instead use ABS(FARM_FINGERPRINT('12345')).
Related
I am working on a solution to compare Datasets from SAP HANA and Azure SQL Server to check consistency of data on SQL server.
Instead of getting all the fields from HANA and doing an "except",
I was thinking of evaluating and comparing a Checksum or Hashbytes on both systems.
However, the Hashvalues for same data is not matching.
Hash Values on SAP HANA
SELECT HASH_MD5(MANDT), HASH_SHA256(MANDT) from SLT_DECO100.MSKU where CHARG = 'UK2031RP' and WERKS = 'U72D'
0x25DAAD3D9E60B45043A70C4AB7D3B1C6
0x47DC540C94CEB704A23875C11273E16BB0B8A87AED84DE911F2133568115F254
Hash Values on SQL Server
select HASHBYTES('MD5', MANDT), HASHBYTES('SHA2_256', MANDT)
from consolidation.MSKU where CHARG = 'UK2031RP' and WERKS = 'U72D'
0xA4DC01E53D7E318EAB12E235758CFDC5
0x04BC92299F034949057D131F2290667DE4F97E016262874BA9703B1A72AE712A
Need support to understand and perform comparison
The hash values could be different based on algorithms what we are using.
Here in the below link comparing the data from two different environments of same tables by providing the pipe delimiters in query.
The pipe delimiters will separates the data from column to column then it gives the accurate results.
Check here for Compare Records Using Hash Values.
Note: More information for the below text in Microsoft Docs,
Algorithms (MD2, MD4, MD5, SHA & SHA1) are deprecated starting with SQL Server 2016 (13.x).
Use SHA2_256 or SHA2_512 instead. Older algorithms will continue working, but they will raise a deprecation event.
Using Oracle SQL Developer, I am trying to make this web (link) example working:
CREATE OR REPLACE FUNCTION concat_self(str VARCHAR2, cnt PLS_INTEGER)
RETURN VARCHAR2 SQL_MACRO(SCALAR)
IS BEGIN RETURN 'rpad(str, cnt * length(str), str)';
END;
/
But I get those errors I do not understand:
Function CONCAT_SELF compiled
LINE/COL ERROR
--------- -------------------------------------------------------------
2/37 PLS-00103: Encountered the symbol "SQL_MACRO" when expecting one of the following: . # % ; is authid as cluster order using external character deterministic parallel_enable pipelined aggregate result_cache accessible
3/4 PLS-00103: Encountered the symbol "BEGIN" when expecting one of the following: not null of nan infinite dangling a empty
5/0 PLS-00103: Encountered the symbol "end-of-file" when expecting one of the following: end not pragma final instantiable order overriding static member constructor map
Errors: check compiler log
Your code is perfectly 'valid' for any instance of Oracle where SQL_MACRO keyword is recognized by the PL/SQL Engine.
The errors start to make a little bit more sense once you realize that the database doesn't understand what you're asking for - it does not recognize that 'SQL_MACRO' is a valid component of the CREATE OR REPLACE FUNCTION PL/SQL library.
Those errors kind of allow you to see how the database's PL/SQL and SQL parser are taking your request and breaking it down into things it knows how to work with.
Everything after the first error is about the parser not being able to make it past the first problem it encountered.
This feature was introduced in version 21c of the database, as explained in the 21c New Features Guide.
You can create SQL Macros (SQM) to factor out common SQL expressions
and statements into reusable, parameterized constructs that can be
used in other SQL statements. SQL macros can either be scalar
expressions, typically used in SELECT lists, WHERE, GROUP BY and
HAVING clauses, to encapsulate calculations and business logic or can
be table expressions, typically used in a FROM clause.
SQL macros increase developer productivity, simplify collaborative
development, and improve code quality.
Сan you help me to convert this Oracle rule to T-SQL.
SELECT CAST(SYS_CONTEXT('CLIENTCONTEXT', 'AccessSubject') AS NVARCHAR2(255)) AS AccessSubjectCode FROM DUAL
I would like to know how this will be in T-SQL : SYS_CONTEXT()
The SYS_CONTEXT('CLIENTCONTEXT', 'AccessSubject') call returns a value configured by the client application. See https://docs.oracle.com/cd/B28359_01/network.111/b28531/app_context.htm#DBSEG98209 for details.
The most similar feature in SQL Server is the CONTEXT_INFO() function. See https://msdn.microsoft.com/en-us/library/ms180125.aspx. However, in SQL Server the context can store just a single value, of maximum 128 bytes (as opposed to Oracle, where there are multiple contexts and you can store multiple named values in each context).
I have some data in a postgres table with one column called version (of type varchar). I would like to use my own comparison function to to order/sort on that column, but I am not sure what is the most appropriate answer:
I have an JS implementation of the style comp(left, right) -> -1/0/1, but I don't know how I can use it in a sql order by clause (through plv8)
I could write a C extension, but I am not particularly excited about this (mostly for maintenance reason, as writing the comparison in C would not be too difficult in itself)
others ?
The type of comparisons I am interested are similar to version string ordering used in package managers.
You want:
ORDER BY mycolumn USING operator
See the docs for SELECT. It looks like you may need to define an operator for the function, and a b-tree operator class containing the operator to use it; you can't just write USING myfunc().
(No time to test this and write a demo right now).
What is the syntax in PostgreSQL for inserting varbinary values?
SQL Server's syntax using a constant like 0xFFFF, it didn't work.
Given there's no "varbinary" data type in Postgres I believe you mean "bytea". Take a look at the docs about the way to specify "bytea" literals.
Depending on the language and the bindings you use there could be more sophisticated ways for transferring binary data - you could find a .Net/C#/Npgsql example here (under "Working with binary data and bytea datatype").