How can manage NULL value in SQL server ?

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Replace Blank value into NULL or N/A. 

  1. Post:44

    Points:310
    Re: How can manage NULL value in SQL server ?

    The different types of NULL values in Database like -

    Blank value.
    Empty value.
    Zero value.
    Optional value.
    Invalid value.
    void value.
    Nothing value.
    Missing value.
    The lowest value.
    Ignorable value.

    1). Handle NULL value by procedure
    
     declare @value int=null;
    if @value is NULL
    begin
      Select 'Value is NULL' AS Result
    end
    set @value=1
    if @value is NOT NULL
    begin
      Select 'Value is not NULL' As Result
    end
    Example for "Temprory Table"
    
    declare @ABC table(Col1 int, Col2 varchar(20))
    
    insert into @ABC values(1,'Test 1')
    insert into @ABC values(2,'Test 2')
    insert into @ABC values(3,'Test 3')
    insert into @ABC values(4,'Test 4')
    insert into @ABC values(5,'Test 5')
    insert into @ABC values(null,'Test 6')
    insert into @ABC values(7,'Test 7')
    insert into @ABC values(null,'Test 8')
    insert into @ABC values(null,'Test 9')
    insert into @ABC values(10,'Test 10') --It returns 3 rows select * from @Temp where Col1 in(1,3,6) --It does not include null so it returns 3 rows select * from @Temp where Col1 in(1,3,6,null)

    1). Use Ascending order

    select * from @Temp order by Col1;

    2). -- Use descending order

    select * from @ABC order order by Col1 Desc

    3).  Null in GroupBy

    select col1 count(col2)
    AS
    from @ABC
    Group By Col1

    4). Case expression

    select CASE when name IS NULL then 'N/A' else name end from Country
    ---where Country is a table---

    5). Using COALESCE 

    Select COALESCE(name, 'N/A') from Countries

    6). ---Return 'N/A' if the name is NULL

    Select IF(name IS NULL, 'N/A', name) from countries
    About to NULL value's facts,

    it is not equal to or similar as any value
    it is not greater than, less than or different from any type of value
    The null value is not equal to NULL itself.
    it is not greater than, less than or different from NULL values.

      Modified On Sep-17-2018 02:28:50 AM

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