I've just started exploring DAX on PowerBI; so please excuse if this query sounds too novice to expert users. DAX functions are too 'different' if coming from a SQL background, hence the query.
In SSIS I'm using a function to replace values in a column based on a string (more so, an error in the value). I'm using the below to do the job easily:
Column2 = SUBSTRING([Column1],1,FINDSTRING([Column1],";#",1) - 1)
Even after looking at the Text functions on Microsoft help page.
for almost an hour trying to understand; I couldn't for some reason.
Any ideas?
An analogous expression in M would be
Text.Middle([Column1], 1, Text.PositionOf([Column1], ";#") - 1)
But you could also use Text.Start instead since you're starting at 1 or make it even simpler with Text.BeforeDelimiter:
Text.BeforeDelimiter([Column1], ";#")
In DAX, you'd use MID/LEFT instead of Text.Start/Text.Middle and FIND or SEARCH (depending on if you need case-sensitivity or not) instead of Text.PositionOf.
LEFT ( [Column1], SEARCH ( ";#", [Column1] ) - 1 )
Either way, the logic is nearly identical but you just have different function names.
Related
I've written a common table expression to return hierarchical information and it seems to work without issue if I hard code a value into the WHERE statement. If I use a variable (even if the variable contains the same information as the hard coded value), I get the error The maximum recursion 100 has been exhausted before statement completion.
This is easier shown with a simple example (note, I haven't included the actual code for the CTE just to keep things clearer. If you think it's useful, I can certainly add it).
This Works
WITH Blder
AS
(-- CODE IS HERE )
SELECT
*
FROM Blder as b
WHERE b.PartNo = 'ABCDE';
This throws the Max Recursion Error
DECLARE #part CHAR(25);
SET #part = 'ABCDE'
WITH Blder
AS
(-- CODE IS HERE )
SELECT
*
FROM Blder as b
WHERE b.PartNo = #part;
Am I missing something silly? Or does the SQL engine handle hardcoded values and parameter values differently in this type of scenario?
Kindly put semicolon at the end of your variable assignment statement
SET #part ='ABCDE';
Your SELECT statement is written incorrectly: the SQL Server Query Optimizer is able to optimize away the potential cycle if fed the literal string, but not when it's fed a variable, which uses the plan that developed from the statistics.
SQL Server 2016 improved on the Query Optimizer, so if you could migrate your DB to SQL Server 2016 or newer, either with the DB compatibility level set to 130 or higher (for SQL Server 2016 and up), or have it kept at 100 (for SQL Server 2008) but with OPTION (USE HINT ('ENABLE_QUERY_OPTIMIZER_HOTFIXES')) added to the bottom of your SELECT statement, you should get the desired result without the max recursion error.
If you are stuck on SQL Server 2008, you could also add OPTION (RECOMPILE) to the bottom of your SELECT statement to create an ad hoc query plan that would be similar to the one that worked correctly.
I just noticed that,
when i execute the following query:
SELECT * FROM tbl WHERE some_key = 1 AND some_foreign_key IN (2,5,23,8,9);
the results come back in the same order they where given in the IN-Statement List,
e.g. the row with some_foreign_key = 2 is the first row returned,
the one with
some_foreign_key = 9 is the last and so on.
This is exactly the opposite behaviour of what this guy describes:
MySQL WHERE IN - Ordering
Can one rely on this behaviour or modify it via some mySQL Server setting?
I know common wisdom is "no ORDER BY Clause" == "RDBMS can sort however it pleases",
but in my current Task at hand this behaviour is quite helpful (really large import)
and it would be great if i could rely on it.
EDIT: I know about the ORDER BY FIELD Trick already, just wanted to know if i can safely avoid the ORDER BY Clause by setting some config somewhere.
ORDER BY FIELD(some_foreign_key, 2, 5, 23, 8, 9)
isn't really that tough to implement - unless you're really simplifying this example. And as you already know it's the only way to be 100% sure of the output ordering.
I have this union statement when I try to take parameters from a form and pass it to a union select statement it says too many parameters. This is using MS ACCESS.
SELECT Statement FROM table 1 where Date = Between [Forms]![DateIN]![StartDate]
UNION
SELECT Statement FROM table 2 where Date = Between [Forms]![DateIN]![StartDate]
This is the first time I am using windows DB applications to do Database apps. I am Linux type of person and always use MySQL for my projects but for this one have to use MS Access.
Is there anther way to pass parameters to UNION Statement because this method of defining values in a form can work on Single SELECT statements. But I don't know why this problem exist.
Between "Determines whether the value of an expression falls within a specified range of values" like this ...
expr [Not] Between value1 And value2
But your query only gives it one value ... Between [Forms]![DateIN]![StartDate]
So you need to add And plus another date value ...
Between [Forms]![DateIN]![StartDate] And some_other_date
Also Date is a reserved word. If you're using it as a field name, enclose it in brackets to avoid confusing the db engine: [Date]
If practical, rename the field to avoid similar problems in the future.
And as Gord pointed out, you must also bracket table names which include a space. The same applies to field names.
Still getting problems when using this method of calling the values or dates from the form to be used on the UNION statement. Here is the actual query that I am trying to use.
I don't want to recreate the wheel but I was thinking that if the Date() can be used with between Date() and Date()-6 to represent a 7 days range then I might have to right a module that takes the values from the for and then returns the values that way I can do something like Sdate() and Edate() then this can be used with Between Sdate() and Edate().
I have not tried this yet but this can be my last option I don't even know if it will work but it is worth a try. But before i do that i want to try all the resources that Access can help me make my life easy such as its OO Stuff it has for helping DB programmers.
SELECT
"Expenditure" as [TransactionType], *
FROM
Expenditures
WHERE
(((Expenditures.DateofExpe) Between [Forms]!Form1![Text0] and [Forms]![Form1]![Text11]))
UNION
SELECT
"Income" as [TransactionType], *
FROM
Income
WHERE
(((Income.DateofIncom) Between [Forms]!Form1![Text0] and [Forms]![Form1]![Text11] ));
Access VBA has great power but I don't want to use it as of yet as it will be hard to modify changes for a user that does not know how to program. trying to keep this DB app simple as possible for a dumb user to fully operate.
Any comments is much appreciated.
Is there any way to directly access the stemmer used in the FORMSOF() option of a CONTAINS Full Text Search query so that it returns the stems/inflections of an input word, not just those derivations that exist in a search column.
For example, the query
SELECT * FROM dbo.MyDB WHERE contains(CHAR_COL,'FORMSOF(INFLECTIONAL, prettier)')
returns the stem "pretty" and other inflections such as "prettiest" if they exists in the CHAR_COL column. What I want is to call the FORMSOF() function directly without referencing a column at all. Any chance?
EDIT:
The query that met my needs ended up being
SELECT * FROM
(SELECT ROW_NUMBER() OVER (PARTITION BY group_ID ORDER BY GROUP_ID) ord, display_term
from sys.dm_fts_parser('FORMSOF( FREETEXT, running) and FORMSOF(FREETEXT, jumping)', 1033, null, 1)) a
WHERE ord=1
Requires membership in the sysadmin
fixed server role and access rights to
the specified stoplist.
No. You can not do this. You can't get an access to stemmer directly.
You can get an idea of how it works by looking into Solr source code. But it might (and I guess will) be different from the one implemented in MS SQL FT.
UPDATE: It turns out that in SQL Server 2008 R2 you can do something quite close to what you want. A special table-valued UDF was added:
sys.dm_fts_parser('query_string', lcid, stoplist_id, accent_sensitivity)
it allows you to get a tokenization result (i.e. the result after applying word breaking, thesaurus and stop list application). So in case you feed it 'FORMSOF(....)' it will give you the result you want (well, you will have to process result set anyway). Here's corresponding article in MSDN.
The following doesn't work, but something like this is what I'm looking for.
select *
from Products
where Description like (#SearchedDescription + %)
SSRS uses the # operator in-front of a parameter to simulate an 'in', and I'm not finding a way to match up a string to a list of strings.
There are a few options on how to use a LIKE operator with a parameter.
OPTION 1
If you add the % to the parameter value, then you can customize how the LIKE filter will be processed. For instance, your query could be:
SELECT name
FROM master.dbo.sysobjects
WHERE name LIKE #ReportParameter1
For the data set to use the LIKE statement properly, then you could use a parameter value like sysa%. When I tested a sample report in SSRS 2008 using this code, I returned the following four tables:
sysallocunits
sysaudacts
sysasymkeys
sysaltfiles
OPTION 2
Another way to do this that doesn't require the user to add any '%' symbol is to generate a variable that has the code and exceute the variable.
DECLARE #DynamicSQL NVARCHAR(MAX)
SET #DynamicSQL =
'SELECT name, id, xtype
FROM dbo.sysobjects
WHERE name LIKE ''' + #ReportParameter1 + '%''
'
EXEC (#DynamicSQL)
This will give you finer controller over how the LIKE statement will be used. If you don't want users to inject any additional operators, then you can always add code to strip out non alpha-numeric characters before merging it into the final query.
OPTION 3
You can create a stored procedure that controls this functionality. I generally prefer to use stored procedures as data sources for SSRS and never allow dynamically generated SQL, but that's just a preference of mine. This helps with discoverability when performing dependency analysis checks and also allows you to ensure optimal query performance.
OPTION 4
Create a .NET code assembly that helps dynamically generate the SQL code. I think this is overkill and a poor choice at best, but it could work conceivably.
Have you tried to do:
select * from Products where Description like (#SearchedDescription + '%')
(Putting single quotes around the % sign?)
Dano, which version of SSRS are you using? If it's RS2000, the multi-parameter list is
not officially supported, but there is a workaround....
put like this:
select *
from tsStudent
where studentName like #SName+'%'
I know this is super old, but this came up in my search to solve the same problem, and I wound up using a solution not described here. I'm adding a new potential solution to help whomever else might follow.
As written, this solution only works in SQL Server 2016 and later, but can be adapted for older versions by writing a custom string_split UDF, and by using a subquery instead of a CTE.
First, map your #SearchedDescription into your Dataset as a single string using JOIN:
=JOIN(#SearchedDedscription, ",")
Then use STRING_SPLIT to map your "A,B,C,D" kind of string into a tabular structure.
;with
SearchTerms as (
select distinct
Value
from
string_split(#SearchedDescription, ',')
)
select distinct
*
from
Products
inner join SearchTerms on
Products.Description like SearchTerms.Value + '%'
If someone adds the same search term multiple times, this would duplicate rows in the result set. Similarly, a single product could match multiple search terms. I've added distinct to both the SearchTerms CTE and the main query to try to suppress this inappropriate row duplication.
If your query is more complex (including results from other joins) then this could become an increasingly big problem. Just be aware of it, it's the main drawback of this method.