Transact SQL :: Database Null Value And String Null
Oct 27, 2015
We have a case where in we should show date based on conditions for e.g if we had a column defined as
col varchar(10) then we would show col as 'NULL' for some condition and actual value when no condition
Normaly date values are stored here e.g under col 20150901 .
Case
when col>'20150901' then 'NULL'
else col
end as Derivedcol
Note this is an extract process and we are presenting data by pumping the data in a table .
Now there is another similar column -colz varchar(10) which stores date but doesnt have case condition so whenever date has no value its shows null which is database null.
So whats the difference between database null and string null ?
How can we show database null for the case condition instead of string "null"?
Hey. I need to substitute a value from a table if the input var is null. This is fine if the value coming from table is not null. But, it the table value is also null, it doesn't work. The problem I'm getting is in the isnull line which is in Dark green color because @inFileVersion is set to null explicitly and when the isnull function evaluates, value returned from DR.FileVersion is also null which is correct. I want the null=null to return true which is why i set ansi_nulls off. But it doesn't return anything. And the select statement should return something but in my case it returns null. If I comment the isnull statements in the where clause, everything works fine. Please tell me what am I doing wrong. Is it possible to do this without setting the ansi_nulls to off??? Thank you
set ansi_nulls off
go
declare
@inFileName VARCHAR (100),
@inFileSize INT,
@Id int,
@inlanguageid INT,
@inFileVersion VARCHAR (100),
@ExeState int
set @inFileName = 'A0006337.EXE'
set @inFileSize = 28796
set @Id= 1
set @inlanguageid =null
set @inFileVersion =NULL
set @ExeState =0
select Dr.StateID from table1 dR
where
DR.[FileName] = @inFileName
AND DR.FileSize =@inFileSize
AND DR.FileVersion = isnull(@inFileVersion,DR.FileVersion)
In my source table, I have columns FirstName and LastName, both of datatype nvarchar. In my dataflow, I created two new derived columns mapped to these two columns. When pushing data to the source, I noticed that the FirstName column had a value of NULL while LastName was just an empty string (for rows that did not have any value).
My question is, why my source table column FirstName is showing a NULL value when the derived column datatype is string and the source is string? It should just be showing an empty string right?
In my report i have CNAME parameter , which allows null value. I checked Allow null value check box in report parameter properties.
when i preview the report , it displays checked NULL check box beside CNAME parameter . I want to give some meaningful name(i.e.ALLCustomers) to this checkbox instead of NULL.
In the flat file SampleID and Product are populated in the first row only, rest of the rows only have values for Rep_Number, Protein, Fat, Solids.
SampleID and Product are blank for the rest of the rows. So my task is to fill those blank rows with the first row that has the sampleID and Product and load into the table.
I don't know enough math to demonstrate that any numerical operationwith a null should yield a null; although I would guess that it's true.I just don't buy it, however, when dealing with strings and nulls. In asimple table with first, middle and last name columns, I would inferthat a null value in the middle name column means the HR person forgotto ask. A zero length string, however, tells me HR did ask and there isno middle name. Regardless of whether HR asked, when I concatenate thethree fields, I can't think of a sound reason why I souldn't get thefirst and last names.Having now started a flame war, I actually have a question: How do Iset the default for any given database or table so that concat nullyields null is permanently off? I have tried exec sp_dboption'myDB','concat null yields null',false (and many variations ondelimiting the parameters) but it doesn't do jack. I can use setconcat_null_yields_null off but that only lasts for the immediatesession.I've tried to follow the thread through the BOL but I'm left scratchingmy head on how to accomplish this.Thanks.Randy
I have a report that is run on a monthly basis with a default date of null. The stored procedure determines the month-end date that it should use should it be sent a null date.
The report works fine when I tell it to create a history entry; however, when I try to add a subscription it doesn't appear to like the null parameter value. Since I have told the report to have a default value of null it doesn't allow me to enter a value on the subscription page.
Now, I suppose I could remove the parameter altogether from the stored proc, but then the users would never be able to run the report for a previous time period. Can someone explain to me why default values aren't allowed to be used on subscriptions when they seem to work fine for ad hoc and scheduled reports? This is really quite frustrating as most of my reports require a date value and default to null so that the user doesn't have to enter them for the latest data.
An internal error occurred on the report server. See the error log for more details. (rsInternalError) Get Online Help
I run a stored procedure for which I have a return variable. The stored procedure returns the ID of a row in a table if it exists:
m_sqlCmd.ExecuteScalar();
The m_sqlCmd has been fed an SQLParameter with direction set to output. When the stored proc returns, I want to test it. Now when there IS a row it returns the ID ok. When the row doesn't exist, in my watch I have:
m_sqlParam.SqlValue with value {Null}
I can't seem to work out how to test this value out. I've tried several things but none seem to work.
This line compiles ok, but the following runs into the IF statement as if the SqlValue is null??
if (m_sqlParam.SqlValue != null).... {
// I'm here!! I thought the watch says this is null??? }
Sorry if this is obvious, but I can't work this one out!!
Looks like there was a fix and then I read this fix is not a fix. Does anyone know how this can be rectified? Does it mean that only Windows authentiation is the only way it works. The Software is over 2 years old, there are no excuses.
I am using sql server 2012. suppose i have a table called cte which contains id and name columns . in name column there are null value . i want to display top row value instead of null value as like attached image. Here is query :
;with CTE As (
Select 1 as Id , 'Advance' as Name union all Select 2 as Id , NULL as Name union all Select 3 as Id , NULL as Name
[Code] ...
Expected Result :
I want to write normal select Query. i am not interest to using loop or cursor.
When building stored procs, I typically have several nullable parameters. Then in the where clause I will either do this
WHERE (@MyParam IS NULL OR MyColumn = @MyParam) or this: WHERE MyColumn = COALESCE(@MyParam, MyColumn) Lately, I've noticed that either of these imposes a performance penalty. In other words, if I change the first one to WHERE MyColumn = @MyParam
without the IS NULL, it is noticeably faster. If I only have one or two nullable parameters, I can separate the logic using IF/ELSE, but it becomes huge if I have a bunch of nullable params.I've looked at the execution plans.
the SQL string below worked, and then started bringing up every record. it should only select records with a value in at least one of the columns, but it apears to be suggesting that all records have some data in one of the columns. if I check the database or the output on the web page there apears to be no data. ?? confused.
"SELECT id, make, model FROM vehicles WHERE workToBeDone1 IS NOT NULL OR workToBeDone2 IS NOT NULL OR workToBeDone3 IS NOT NULL OR workToBeDone4 IS NOT NULL OR workToBeDone5 IS NOT NULL"
Any ideas how I could implement this more robustly? cheers M
Folks, this isn't exactly a 'Getting Started' question, but I couldn't find a more appropriate Application Development forum.
I'm porting an open source PHP application (http://sourceforge.net/projects/gallery) to use SQL Server as a backend. One of Gallery's unit test scripts tests the ability to insert a string containing a NULL character ( ). It's OK if the string is truncated during insertion, just so long as everything before the is there.
The string being inserted looks like:
$testString = "The NULL character should be escaped !";
(Note the between "escaped " and " !")
The error that the Gallery test script is getting is:
[Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near 'The NULL character should be escaped '.] in EXECUTE("INSERT INTO g2_PluginParameterMap (g_pluginType, g_pluginId, g_itemId, g_parameterName, g_parameterValue) VALUES ('module','unitTestModule',1,'test19476','The NULL character should be escaped !')")
It looks like SQL Server is complaining about the syntax. I've written a much simpler test script in the hopes of reproducing the problem, but I don't know if what I'm now hitting is the same problem or a different one.
// Connect to the db $db = new COM("ADODB.Connection") or die("Cannot start ADO"); $db->open($connectString);
// Drop & recreate the table $db->Execute ($sqlTableDrop); $db->Execute ($sqlTableCreate);
// Insert the test data //$testString = "The NULL character should be escaped !"; $testString = "This is a test string."; $res = $db->Execute("insert into ljmtemp (col1) values ('$testString')"); if (!$res) die ("INSERT failed");
// Disconnect from the db $db->Close();
?>
And it results in:
C:MyServer>php testMsSqlInsertNull.php PHP Fatal error: Uncaught exception 'com_exception' with message 'Source: Microsoft OLE DB Provider for ODBC Drivers Description: [Microsoft][ODBC SQL Server Driver][SQL Server]Unclosed quotation mark after the character string 'The NULL character should be escaped '.' in C:MyServer estMsSqlInsertNull.php:27 Stack trace: #0 C:MyServer estMsSqlInsertNull.php(27): com->Execute('insert into ljm...') #1 {main} thrown in C:MyServer estMsSqlInsertNull.php on line 27
I'm not sure if this is the same problem as Gallery is reporting or another one.
It looks like somebody is treating the as a string terminator, but when i double the backslash the literal ' ' is inserted into the database.
How can I get SQL Server to insert at least everything up to the ?
Hopefully once I have my simple script working I'll be able to figure out what's wrong in the Gallery test.
I am using Visual Web Developer Express 2005 and SQL Server Express 2005. I have set up a trigger that fires when an update has been performed on a specific table. The trigger checks to see if specific columns have been updated. If they have, then the trigger code is executed. This part works fine. I am now trying to find a way to check if null values exist in either one of two field from the same table. If either field contains a null value, then I don't want the trigger code to be executed. How can I check for null values and skip a block of code within my Transact Sql trigger. Thanks.....
I need to check in my Stored procedure if the information passed is null or empty so I can decided to insert the new value or keep the old. How do I accomplish this please in T-SQL. Thanks in advance.
Hi: Trying to insert null value into sql table, but not working, if I use: if (strMyText.Length == 0) command.Parameters.Add("@Text", DBNull.Value); // or using:("@Text", null), or using:("@Text", DBNull) else command.Parameters.AddWithValue("@Text", strMyText); When I go back to table, I see the value is: 'NULL', has single quotation mark, suppose to be: NULL Where is the problem? Thanks a lot. Jt
Hi all, I have some columns in my database which allows null. I want to know if leaving the field to be NULL or storing an empty string into the field, which will take up more space?? if the field type is varchar(100)
I've have about 100 tables, for some reasons, column values that are originally NULL was inserted as emtpy string. So, I am wondering if I can write JUST ONE SQL (hopefully don't have to specify the field names in the SQL as well) for each table so that all the empty strings will be converted back to NULL.
Hi!I got a column, with different dates in it (Ddata type "nvarchar")...when running a SELECT on this column, I'm trying to filter thoserecordsets out, WHERE this column is NULL (I checked the table, thereare "empty" fields in the column):"SELECT bla FROM bla WHERE myColumn NOT NULL"but I still receive those "empty" fields in my resultset ...so I tried it with:SELECT bla FROM bla WHERE myColumn <> ''again, "empty" fields in my resultset ....what's going wrong there? is there a possibility to check what kind ofvalue I got in my column!?Thanks!Peter
I'm importing a flat file with date fields into a sql table. I'm using a script transformation, reading the "normal" date fields into a string, massaging them, and passing them to a database table which uses standard datetime fields. No problem yet.
The file also contians a number of date fields that are all blanks. These correspond to "NULL" values. The problem is in my script I'm trying to do something like this:
(for database) (in SSIS)
date field = System.DBNULL.Value
This is wrong and I get complaints about improper data conversion, etc. What can I pass in the output string that the database will intepret as a NULL?
I am getting this error: "Cannot insert the value NULL into column 'OrderID', table 'outman.outman.Contact'; column does not allow nulls. INSERT fails." -- But my value is not null. I did a response.write on it and it show the value. Of course, it would be nice if I could do a breakpoint but that doesn't seem to be working. I'll attach a couple of images below of my code, the error, and the breakpoint error.
Server Error in '/' Application.
Cannot insert the value NULL into column 'OrderID', table 'outman.outman.Contact'; column does not allow nulls. INSERT fails. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'OrderID', table 'outman.outman.Contact'; column does not allow nulls. INSERT fails.Source Error:
Line 89: sContact.Phone = sPhone.Text.Trim Line 90: sContact.Email = sEmail.Text.Trim Line 91: sContact.Save() Line 92: Line 93: Dim bContact As Contact = New Contact()Source File: F:InetpubwwwrootOutman KnifeCheckout.aspx.vb Line: 91 Stack Trace:
hi,my structure table in database:Amount float(53) not null default 0when i try to run his script:alter table ABC alter column Amount float(53) nullit can only set the Amount to allow null, but can't set the defaultvalue to empty.anyone know how to set the field to allow null and default set toempty, no value.thanks
