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1
vote
1answer
106 views

Simple query not returning blank records

Very simple example here to a very frustrating treasure hunt for the mystery character. I have a table with a varchar(1) NOT NULL column - everything default - ANSI_PADDING & NULLS are ON for the ...
1
vote
3answers
5k views

Oracle empty string converts to null

When doing an insert, an empty string is converted to null: insert into test (f) values (''); Now, there is a row with f containing a null. But, when I query the table, I cannot use '': select * ...
3
votes
3answers
1k views

Empty LONGTEXT or NULL?

In my MySQL DB I have one field called html_contents that contains all the html to be shown in a webpage. Obviously the html could be huge, and certaintly bigger than 64KB, therefore I decided to use ...
1
vote
1answer
1k views

Query performance of a NULL vs an empty ('') varchar in SQL Server 2012

I have 3 indexed fields in a query: int, int, and varchar(250). The query performs well when all 3 conditions are specified with real values. The int columns always have values, but there are plenty ...
2
votes
3answers
9k views

Questions about handling NULLs and empty strings in nvarchar and numeric fields

I understand that questions similar to these pop up often around here. I have searched before posting these but I didn't find any QA threads that completely answer my questions. In a table, I ...
3
votes
2answers
419 views

Remove nulls from TSQL connection string

I have a bunch of queries, against a couple different databases, that I use to generate delimited reports. I'm trying to create some new reports against a MSSQL database and I'm having trouble ...
9
votes
1answer
3k views

Empty Strings: Why or when is '' equal to ' '?

Who can explain why select case when '' = ' ' then 1 else 0 end, LEN(''), LEN(' '), DATALENGTH(''), DATALENGTH(' '); yields ----------- ----------- ----------- ----------- ----------- 1 ...
3
votes
4answers
2k views

Should I convert empty varchar values to NULL?

I have a stored procedure which accepts various varchar parameters. The middle tier code which calls the procedure has not been consistent in terms of the values it submits. For example, sometimes a ...
46
votes
7answers
13k views

When to use NULL and when to use an empty string?

I'm interested mainly in MySQL and PostgreSQL, but you could answer the following in general: Is there a logical scenario in which it would be useful to distinguish an empty string from NULL? What ...