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Is there an empty statement keyword in T-SQL in Sql Server 2005 or newer? Something like NULL statement in PL/SQL.
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NULL is used in SQL to indicate that a value doesn't exist in the database. It's not to be confused with an empty string or a zero value. While NULL indicates the absence of a value, the empty string and zero both represent actual values.
The IS NULL constraint can be used whenever the column is empty and the symbol ( ' ') is used when there is empty value.
In this article, we will look into how you can set the column value to Null in SQL. update students set Gender = NULL where Gender='F'; SELECT * FROM students ; Output: Column value can also be set to NULL without specifying the 'where' condition.
The SQL NULL is the term used to represent a missing value. A NULL value in a table is a value in a field that appears to be blank. A field with a NULL value is a field with no value. It is very important to understand that a NULL value is different than a zero value or a field that contains spaces.
You can declare a label to do nothing.
DECLARE @value INT IF @value IS NULL BEGIN no_op1: END ugly happens sometimes. I believe their is a valid use. In a lengthy/complicated decision branching structure with several if else statements, some of those statements may contain conditions in which you specifically desire no action. You also don't want those condition falling thru do the default else, where certain work is done. In that case, it's a valid use.
Here are two ways to do this - see B and C
Declare @status as char(1) set @status = 'D' If (@status = 'A') select 'Great!' Else if (@status = 'B') begin if null=null select null -- predicate never resolves true end Else if (@status = 'C') set @status = @status -- set a variable to itself Else select 'Needs work!' Note, this is an over-simplified example. It is best used for readability when conditions are complex.
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