Questions tagged [empty-string]

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How to pass array of UUIDs *OR* empty array and return implicit (inner join)?

How would I pass a list that is either full of UUIDs or empty, then return only joined records with those id values or all records if empty? This question (Casting an array of texts to an array of ...
0
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2answers
1k views

COALESCE with cast

I'm pulling data from a jsonb column in Postgres, and casting it to an integer to compare it against a count. The problem is that in some cases the data apparently can't be cast to integer and I get: ...
1
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1answer
2k views

Empty string values - PostgreSQL 9.2 [closed]

I've got some empty string values being putting into my DB. Code I've used: CREATE FUNCTION get_as_byte_array(anyelement) RETURNS INTEGER[] AS $$ SELECT CASE WHEN length($1::...
1
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1answer
893 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 ...
6
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4answers
34k 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
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3answers
6k 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 ...
3
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1answer
5k 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 ...
3
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3answers
29k 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 ...
4
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2answers
711 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 ...
17
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1answer
5k 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 ...
4
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4answers
4k 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 ...
79
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9answers
62k 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 ...