What Is The Difference Between Updating Null Value Vs Empty String To Varchar/char Field?
Aug 29, 2007
Hi,
What is the difference updating a null value to char/varchar type column
versus empty string to char/varchar type column?Which is the best to do and why?
Could anyone explain about this?
Example:
Table 1 : tCountry - Name varchar(80) nullable
Table 2 :tState - Name char(2) nullable
Table 3 :tCountryDetails - countryid,state (char(2) nullable) - May the country contain state or no state
So,when the state is not present for the country ,i have two options may be - null,''
tCountryDetails.State = '' or tCountryDetails.State = null?
I am using the following query to calculate date differences:select ..........DATEDIFF(d, recruitment_advertising.advertising_date, career_details.RTS_Email AS Datetime) AS Ad_to_RTS_days FROM .....I have stored all my dates as NVARCHAR because of the issues with localization.If the value is an empty String my output is eg: -38700. which is way off and incorrect. Some of the values in my table are NULL and they produce the correct result.Is there a T-SQL statement to replace empy Strings with the NULL value in my tables.I'd like to use it as a trigger when inserting or updating to convert empty strings to NULLbefore the values are inserted.Thanks guys.
i have a trigger on a table right now... when fields are inserted, theres a text field inserted and i want to check if that text field = '' (the empty string, not NULL) and if it doesn't equal that, then perform some row updates on other tables, but if it is empty, to not do anything else in the trigger... right now i have this:
Code:
IF ((SELECT Note FROM XATPoDetail WHERE ReqNbr = (SELECT ReqNbr FROM Inserted)) LIKE(''))
Note is the text field, XATPoDetail is the table where its being inserted into. I had to do the select FROM the table because it wouldn't let me select a text data type from the "Inserted" virtual table
but it tells me me "Error 279: The text, ntext, and image data types are invalid in this subquery or aggregate expression"
i have a trigger on a table right now... when fields are inserted, theres a text field inserted and i want to check if that text field = '' (the empty string, not NULL) and if it doesn't equal that, then perform some row updates on other tables, but if it is empty, to not do anything else in the trigger... right now i have this:
IF ((SELECT Note FROM XATPoDetail WHERE ReqNbr = (SELECT ReqNbr FROM Inserted)) LIKE(''))
Note is the text field, XATPoDetail is the table where its being inserted into. I had to do the select FROM the table because it wouldn't let me select a text data type from the "Inserted" virtual table
but it tells me me "Error 279: The text, ntext, and image data types are invalid in this subquery or aggregate expression"
I have one question to all SQL Guru's I know the basic difference between CHAR and VARCHAR of CHAR taking all the space it is declared with and VARCHAR taking only amount of space used.
I want to know or link to any doucment which gives the difference between CHAR and VARCHAR more than what is mentioned above.
Hi All: I am new to Sql 2000 database,Now I'm planing to create a table in my databse,my table included below fields like this : PoNo(the length is 15 characters) ,Supplier Name(the length is 50 characters).etc but I don't how to select the datatype for them. should I select Char or VarChar ? which one is the best slection ? thans in advanced!
Would it be OK to use varchar(5) instead of char(5) as the first field of acomposite clustered index?My gut tells me that varchar would be a bad idea, but I am not finding muchinformation on this topic on this when I Google it.Currently the field is Char(4), and there is a need to increase it to hold 5characters.TIA
I'm trying to do a simple update like I have done countless timesbefore.However, when I update the empty fields in this table it places a -1into the field rather than the enterred value.It is indexed with duplicates allowed. It says that zero lenght isset to yes.What can I do about this?if Request.form("ouserid") <> "" Thenvar2 = " and userid = '" & Request.form("ouserid") & "' "Elsevar2 = " and userid is null "End ifif Request.form("orepid") <> "" Thenvar1 = " repid = '" & Request.form("orepid") & "'"Elsevar1 = " repid is null "End if"Update [Website Settings] set userid = '" & REquest.form("userid") &"' and repid = '" & Request.form("repid") & "' where " & var1 & var2& var3Thanks!
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.
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?
Hiya! I'm having a problem updating a varchar(4000) column in Enterprise Manager when I open the table and try to update one particular row directly. Most of my rows have approx. 100-500 characters in this column, and I can update all of them them, but one row which has 1976 characters in this varchar column doesn't let me change data by typing directly into this column, although it will let me update other columns in the same row. Altogether, my row size has a max. of approx. 5000, below the 8060 limit, so I doubt that's the problem. What Is?
Hi all,I have this code that I use for my Search function:SELECT DISTINCT [MUSIC_TITLE], [MUSIC_ORIGINAL_SINGER], [MUSIC_PERFORMER]FROM t_musicWHERE (@MUSIC_TITLE IS NULL OR [MUSIC_TITLE] LIKE '%' + @MUSIC_TITLE + '%') AND (@MUSIC_ARTIST IS NULL OR ([MUSIC_ORIGINAL_SINGER] LIKE '%' + @MUSIC_ARTIST + '%' OR [MUSIC_PERFORMER] LIKE '%' + @MUSIC_ARTIST + '%')) But right now if I don't enter anything in one of the textbox (2 have two, either of them can be left empty), the above Sql statement doesn't return anything since ADO.NET can't tell an empty textbox and treat it at null... So anyone please help me how to detect an empty textbox and set that to null for the above SQL statement to work. (It work in SQL Manager Studio, when I set one of the parameter = null.) I'm very new to ASP.NET stuffs, so if someone can help me to convert that function to code-behind and help me to call it from the .aspx, that would be even better as I don't want to put the code in my .aspx page... But I'm not quite there yet. Thank you all,Kenny.
I would like to update a varchar field with an update statement that appends information to what is currently stored in the field, for example in the Statement field I may currently have a name (Mark) and I want to add a unique identifier to the end of the name so that it may look like, Markq1572, is there a way to do this in an update statement?
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.
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 SSIS flat file import using fastload, I'm trying to import data into SQL 2005 previously created tables.
The table may contain column that are NULLable BUT there is NO DEFAULT for them.
If the incoming data from flat files contains nothing either between the delimeters, how can I have a NULL value inserted in the column instead of blank/empty string?
I didn't find an easy flag unless I'm doing something wrong. I know of at least two ways to do it the hard way:
1- set the DEFAULT(NULL) for EVERY column that needs this behaviour
2-set up some Derived Column option in the package to return NULL if the value is missing.
Both of the above are time consuming since I'm dealing with many tables. Is there a quick option to default the value to NULL WHEN there is NO data ELSE insert the data itself? So the same behavior that I have right now except that I want NULL in place of empty string/blank in the varchar(x) columns.
SELECT * FROM PABX INNER JOIN LOGIN ON (PABX.COD_CLIENTE = LOGIN.COD_CLIENTE) AND LEFT(LOGIN.TELEFONE1,3) = LEFT(PABX.NRTELEFONE,3) LEFT JOIN AUXILIAR ON (AUXILIAR.ORIGEM=LOGIN.LOCALIDADE) WHERE pabx.COD_cliente = 224 and SUBSTRING(PABX.NRTELEFONE,4,1) NOT IN ('9', '8', '7') AND LOGIN.UF = RIGHT(PABX.LOCALIDADE,2) AND LOGIN.LOCALIDADE <> PABX.LOCALIDADE AND PABX.CLASSIFICA IS NULL AND PABX.LOCALIDADE <> AUXILIAR.DESTINO AND (BLOQUEADO = 0 OR BLOQUEADO IS NULL)
But It has a problem because when AUXILIAR.DESTINO returns null (it means there is no registry) the condition AND PABX.LOCALIDADE <> AUXILIAR.DESTINO doesn't work, like 'SAO PAULO' is different from 'NULL' but for my query no it's not even equal, and this condition ommit the results....how can I solve it ?
PS: Both auxiliar.destino and pabx.localidade is varchar(255)
I need to pass in null/blank value in the date field or declare the field as string and convert date back to string.
I tried the 2nd option but I am having trouble converting the two digits of the recordset (rs_get_msp_info(2), 1, 2))) into a four digit yr. But it will only the yr in two digits. The mfg_start_date is delcared as a string variable
option 1 I will have to declare the mfg_start_date as date but I need to send in a blank value for this variable in the stored procedure. It won't accept a null or blank value.
I have a requirement where i have to insert empty string in column whose datatype is decimal.
I have to replace the column value if it is null then insert it as ' '.
Obviously its generate error msg for conversion, is there any workaround for this. I cannot add 0 or other value as this column is used to generate some output value.
IIF(Column1 IS NULL, ' ', Column1))
I used TRY_PARSE but it insert null value if there is conversion error.
If I create a row with a nullable text column whose initial value is null and then update the column with a value that is exactly 256 characters long, the value remains null. Once I update the column to any other value (including null), it works as expected. I have not yet seen a way around this.
I have a table that holds a large amount of text in a field that is the body of the email. For example, it might say something like:
Quote: Email tech support at thisemail@email.com if you have any questions about the results of this test.
I need to change the email address in this field. Using this example I need to change thisemail@email.com to thatemail@email.com; however I do not want to change the other text in that field.
It is also important to note that the rest of the body of the emails stored here is different depending on the email.
So basically what I need is a statement that would look at a particular field, search for an email address, and replace that email address with another one without disturbing the rest of the text in that field. I already checked the w3 update tutorial and the update there is for the entire field.
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 have a table that contains a lot of demographic information. The data is usually small (<20 chars) but ocassionally needs to handle large values (250 chars). Right now its set up for varchar(max) and I don't think I want to do this.
How does varchar(max) store info differently from varchar(250)? Either way doesn't it have to hold the container information? So the word "Crackers" have 8 characters to it and information sayings its 8 characters long in both cases. This meaning its taking up same amount of space?
Also my concern will be running queries off of it, does a varchar(max) choke up queries because the fields cannot be properly analyzed? Is varchar(250) any better?
Should I just go with char(250) and watch my db size explode?
Usually the data that is 250 characters contain a lot of blank space that is removed using a SPROC so its not usually 250 characters for long.
I'm trying to find a specific string (a name) and replace it with another inside of a VARCHAR(7000) field. Unfortunately, there are names like Ted and Ken that I'm trying to replace. I would like to leave words like Broken, admitted, etc... intact.
UPDATEtbl SETBody = LEFT(REPLACE(tbl.Body, pm.OldFirstName, p.FirstName), 7000) FROM Table tbl JOIN Person p ON p.PersonID = tbl.PersonID JOIN PersonMap pm ON pm.PersonID = p.PersonID AND LEN(pm.OldFirstName) > 2 WHEREtbl.Body LIKE '%[^a-z]'+pm.OldFirstName+'[., ]%
'The problem I'm running into is that the '[, ]%' in the LIKE excludes any record that ends with the FirstName because it is requiring either a space, comma or period after the name. Is there some way to add an empty string to the list of acceptable characters as that would cover any scenario in the data? I would prefer not to add all characters except space, comma and period, but I guess I could do that.
