在sql中联接两个表时将空值替换为0而不是null

Question

I have join two tables t1 and t2. The output produces some null records since there is no data in the table t2. Instead of showing null I want to show 0 since I have to perform some arithmetic operation in the crystal reports. please help me.....

Answer 1

sample example

declare @t table (ID int)
declare @t1 table (ID int)

insert into @t (id) values (1)

select t.ID,ISNULL(TT.ID,0)id  from @t t
LEFT JOIN @t1 tt
ON t.ID = tt.ID 

Answer 2

Use the COALESCE function which automatically replace null values as 0 . Sample

SELECT COALESCE(total_amount, 0) from #Temp1