Question

I am novice to sql

I have a table1 with [month], [forecasted avg. temperature] as columns. I have another table2 with [month], [actual avg. temperature] as columns. Now for some dates, there is no records available in table one. In that case I would like to pull records from the table2 if I have available record in that table.

for example table 1 may have records from april to dec for a year say 2010. table 2 has the records for jan to dec for 2010 year. I would like to pull records from table 2 for the mising jan, feb, mar months records in table 1.

Any idea. we are using sql server 2008

Thanks in advance.

Answer 1

select 
   [month], isnull([forecasted avg. temperature], [actual avg. temperature]) as temperature 
from 
   table2 left outer join table1 on table1.[month] = table2.[month]

UPDATE
per comment from Dems, I changed the query. The original post makes it sound as though table2 includes data for all months, so rather than a FULL JOIN, I just switched so it will pull all records from table2, and join if available to table1, continuing to use ISNULL for the temp. If table2 does not include all data, then a FULL JOIN is necessary.