if it’s not a foreign key field, not using empty strings could save you some trouble. only allow nulls if you’ll take null to mean something different than an empty string. for example if you have a password field, a null value could indicate that a new user has not created his password yet while an empty varchar could indicate a blank password.
NULL means absence of value (i.e. there is no value), while empty string means there is a string value of zero length. For example, say you have a table to store a person’ data and it contains a Gender column.
for the philosophical question, the answer is similar: validate your inputs. If an empty string is a valid value for the field in question, then expect it and code for it; if not, use null. An empty string would be a valid input to answer the question: What did the mime say to the giraffe?, 1/9/2009 · I don’t know reallly much about the GEOGRAPHY types, but to me this sounds remarkably like the NULL vs empty string debate. Store an empty string if you know that a person does not have a middle initial. Store NULL if you have no information to store about a persons middle initial.
3/27/2009 · The design of software – good discussion on null vs empty string – here. SQL Batman’s post on SQL Server and Null values – here and then the post by Aaron Alton – here. Very good articles. Empty strings and default values – here. We covered above the integer, datetime and string fields, this post from Madhivanan covers other data …
I would like to know how to use NULL and an empty string at the same time in a WHERE clause in SQL Server. I need to find records that have either null values or an empty string . Thanks.
By using NULL you can distinguish between put no data and put empty data. Some more differences: A LENGTH of NULL is NULL, a LENGTH of an empty string is 0. NULLs are sorted before the empty strings. COUNT(message) will count empty strings but not NULLs. You can search for an empty string using a bound variable but not for a NULL. This query:, 9/11/2014 · There are some values lower than empty string /space. Unfortunately there is no way of distinguishing between an unknown value or a missing value in standard sql, hence the NULL.
11/5/2012 · How do you filter a SQL Null or Empty String? A null value in a database really means the lack of a value. It is a special “value” that you can’t compare to using the normal operators. You have to use a clause in SQL IS Null. On the other hand, an empty string is an actual value that can be compared to in a database.
11/6/2020 · The only suggestion is not to use empty strings but use NULL values instead which can be handled by the ISNULL, NULLIF and COALESCE functions. Introducing a Custom Function for Handling Null and Empty Values . Additionally you can always create your own user-defined scalar-valued function that can deal with the issue of the empty string values.
