how to use DataTable.Select() to select Null/ empty values?

Question

My data table filled from db is having empty values in some cells.

The results database SP return has Null in them but in DataTable these values are appearing as '' or empty cells.

Please guide me how to use Select() to select these dbnull/ empty rows.

Thanks

Any specific column? Or you want to select rows with any column of NULL or empty? — Thit Lwin Oo
– Thit Lwin Oo, Commented Feb 17, 2012 at 7:01

pb2q · Accepted Answer · 2012-10-09 15:07:07Z

103

The correct way to check for null is to check for it:

DataRow[] myResultSet = myDataTable.Select("[COLUMN NAME] is null");

edited Oct 9, 2012 at 15:07

pb2q

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answered Oct 9, 2012 at 15:02

James McG

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6 Comments

Franck LEVEQUE Over a year ago

I've seen this answer in a lot of place but no reference to where it is documented. DataColumn.Expression is actually the only refernce I found and doesn't talk about it. Is it documented anywhere ?

daro Over a year ago

Are the '[' and ']' necessary? If so, why? Thanks in advance!

JJS Over a year ago

@daro because the column name has a space

mzonerz Over a year ago

this is the only answer worked for me(tried [COLUMN NAME] ='' AND [COLUMN NAME] ='"+DBNull.Value+"' )

Mandz Over a year ago

this should be the proper answer for the question

|

Thit Lwin Oo · Accepted Answer · 2012-02-17 07:07:15Z

7

For one column

DataRow rows = DataTable.Select("[COLUMN 1]=''");

For more than one column

DataRow rows = DataTable.Select("[COLUMN 1]='' OR [COLUMN 2]=''");

answered Feb 17, 2012 at 7:07

Thit Lwin Oo

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4 Comments

SandhraPrakash Over a year ago

Does this actually work for both null and empty values? I have tried these and is not working for me. I have both null and empty values in the cells.

Mandz Over a year ago

this only detect blank value and not null.

Stiegler Over a year ago

Ok for text columns, but beware. This will throw a System.Data.EvaluateException for datetime columns. "Cannot perform '=' operation on System.DateTime and System.String."

stigzler Over a year ago

This does not detect null. This detects empty string. See James McG's answer for correct solution.

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