Within A SELECT, How Do I Replace An Empty Or Null Value With A Value From Another Table?
Apr 20, 2008
Hello,
I'm a beginner in SQL and I have been searching through the SQL Cookbook and Google but I can't seem to find an example of what I want to do.
I want to create a report that will return names and emails using two of my tables. I want to use the email in my primary table in the select but if it is null or empty I want to replace it with an email from my secondary table.
Below is what I would like to do but I got a syntax error with it in SQL Server 2000.
SELECT MemberID As ID,
MemberFirstName As FirstName,
MemberLastName As LastName,
(IF MemberEmail = '' THEN SELECT TOP 1 OtherEmail FROM OtherTable WHERE OtherID = MemberID) As Email
FROM PrimaryTableThanks for your time.
Jason
Ok.. so I have a fixed position data feed. I read the file in as just whole rows initially, process a specific position and evaluate a conditional split to determine direction of the file for proper processing (file contains multiple recors with different layouts). This all works fine. I then use the derived column feature to process all the columns.
Most of the columns are as simple as SUBSTRING(RecordData,1,10) for example to get the first column. This all works for string data. I then have a column that is a date field. The problem occurs that the code SUBSTRING(RecordData,20,10) returns either a date or empty set of data if no date was in the original file. When this gets sent to the OLEDB connection (SQL Server 2005) into the date field it fails. If the record has a date it works, but if it is empty it fails the insert.
I tried to replace empty strings with NULLs with this code. REPLACE(TRIM(SUBSTRING(RecordData,20,10)),"",NULL(DT_WSTR,10)). This does not work. So my question is how do I bring a date field from a fixed flat file into a SQL datetime field using a derived column? More specifically is how do I set it to NULL if its empty data? When I use the above code it inserts all the rows from the file, but it sets all rows to NULL not just the empty ones.
1. Have a query that fetches a real value (e.g. 4.3345643)
Let say the field is called TheReal.
How can I format the value in the select statement so I get a thousand separator(s) and two decimals in the resultset.
2. In the same query I have a left join as well. Table 2 retur (sometimes) <NULL>. Is it possible to force this <NULL> value to be a fixed string value instead in the select statement.
Damn! SQLServer2000 can't add a NOT NULL COLUMN even in one emptyexisting table!That is, A is the existing table and it is emtpy, I want to add one NOTNULL COLUMN (col_new) to A using following T-SQL statement, then itwill fail.ALTER TABLE A ADDcol_new varchar(600) NOT NULLGOYou should change it to these statements in SQLServer2000:ALTER TABLE A ADDcol_new varchar(600) NULLALTER TABLE A ALTER COLUMN col_new varchar(600) NOT NULLGOah, ridiculous! right?Fortunately, this stupid behavior is changed in SQLServer2005. Thefirst T-SQL statements works.
I have an app which uses SQLDataSource to update the information to database (SQL Server 2000). Is there a way to trim the input of users somehow (blank lines) ? For example if I have an Comments-textarea on my form and users enter text to it, can I somehow take out the extra blank lines out of that textarea before submitting the data to database ? I know how to do this programmatically, but was just wondering if this could be done when using SQLDataSource-control. I'm using DataReader to extract the information from database to an CSV-file. Because of the blank lines, occasionally CSV are really messed up because of that. Is there a way to remove the blanklines when iterating the DataReader values ?
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
I have an automatic data collection system. The large majority of the time, all data is electronically gathered. On occasion, the need arises to substitute a manually entered value into the data when a valuable piece of information cannot be electronically secured. When a piece of data is open to substitution, it arrives with a value of -9999 (a value not naturally occuring) in Table A. I want to be able to use a trigger on table A to get its substitution value from a corresponding column (Same name) in Table B. Tables A & B will have an identical schema. A is raw data, B is the manually updated table. Any value in the raw table with the content of -9999 gets its replacement from Table B.
I have a query that returns the appropriate values I need, however there is one field I'd like to add and utilize but my problem is I only want to use it if it contains data.
If I filter it with IS NOT NULL it returns all the records, including the empty records. The field is simply empty, and doesn't come back as NULL. If I filter it with =' ' , it shows all the records with the empty records only.
I need to do the opposite, be able to filter it only if it's not empty.
I've inherited a terribly designed database. When cells in the tables have nothing in them, rather than being NULL, they're just empty. So now I can't use COALESCE...
Is there a way for COALESCE to check if a cell is empty instead of NULL? And if not, is there a way to get around this?
I need to separate the data from one column in to two columns based on the transaction type TRAN_TYPE (C is credit, D is Debit)
TRAN-TYPE| AMOUNT C 20.00 D 30.00 C 50.00
To do that I have this code:
select CASE WHEN TRAN_TYPE = 'D'THEN CAST (ISNULL(amount, 0) as varchar (30)) end as DEBIT, CASE WHEN TRAN_TYPE = 'c'THEN CAST (ISNULL(amount, 0) as varchar (30)) end as CREDIT FROM HISTORY
Can a Trigger be created to automatically replace NULL values with "-"? Suppose I have an Entry Form with 20 Text Boxes. I don't want to code in my application. I want that when an Insert Query is executed, a BEFORE/AFTER TRIGGER should be executed to replace the NULL values coming from Insert QUery to "-".
I also want to know whether to use a Trigger or a Function/Stored Procedure.
I have a colunm name (Countystcd) in a matrix, and i have used the mentioned colunm in Data Region of Matrix which shows thw sum of count for each state, i want to replace null with 0 in report please help me in this regard.
INSERT INTO #tmpTable (eventName) values ('Another One')
DROP TABLE #tmpTable
this causes a null insert issue
(0 row(s) affected)
Msg 515, Level 16, State 2, Line 7
Cannot insert the value NULL into column 'statuspid', table 'tempdb.dbo.#tmpTable___________________________________________________________________________________________________________000000000130'; column does not allow nulls. INSERT fails.
The statement has been terminated.
So how do I allow the null, as the not null is coming from the ES table. But I want to allow the insert to happen without having to create the table first, this code works in SQL 2000 but fails in 2005, inserting all fileds into the insert also has it's own issues as some of the fields are delibertly left blank so in some circumstances the data returned to a grid displays correctly.
This method has been used in quite a lot of stored procedures and will be a nightmare to correct if each has to be edited.
One example of the use of is to return a dataset and then add a row at the bottom which is a sum of all the rows.
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
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Well met,
Let's say I have a web form that allows users to insert and update records in a SQL database. Is it better to set empty web controls (textbox, etc.) to DBNull or let it go as an empty string into the database?
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.
I added a new field to an existing ETL process which uses SSIS to ingest a CSV file. The new field in the file, Call_Transaction_ID, will not always be populated for every record and so can be NULL or empty for certain records.
Here's the problem:After the file is extracted into a staging table, the Call_Transaction_ID field is showing blank or empty when it has no ID for that particular record. The problem is when I try to then ETL this data into a fact table - I'm trying to set the Call_Transaction_ID field to -1 if it is NULL or empty, however SQL Server doesn't see the field as empty even though there is no value in the field so -1 will NEVER return.
Using a WHERE DATALENGTH(Call_Transaction_ID) = 0 returns 0 records, again because SQL Server doesn't see the field as empty or NULL.
What do I do now to get around this? How do I fix it?
declare @user varchar(30) = '' if(@user is not null or @user <> '') BEGIN print 'I am not empty' END ELSE BEGIN print 'I am empty' ENd
The output should be 'i am empty' but when i execute this i am getting ' i am not empty'. even i did browse through but i don't find the difference in my logic.
I have always (or at least intended to) treat NULL and empty strings separately in my SQL querying history. Now I have run across something that mystifies me (but probably shouldn't) that I would like an explanation for.
Consider this bit o' code:
DECLARE @ORDER CHAR(10) SET @ORDER= ( SELECT NULL ) IF @ORDER <> '' PRINT 'Not an empty string'
IF @ORDER IS NULL PRINT 'It is NULL'
Run this and you will get:
It is NULL
I was expecting:
Not an empty string It is NULL
Why is NULL not passing the 'not an empty string' test? In other words, how does NULL = '' ? Is NULL cast to an empty string for this comparison?
Hi,I run a stored procedure with a parameter given from a text box in an accessadp. If the text box is empty then what is passed to the parameter? I can'tseem to get it to flag up as either null, or 0 length.Any tips?Cheers,Chris
