[ADMIN] case statement to cath nulls on joined tables

[John Morgan]

Hello,

I am doing a left outer join between a polygon table and a data table.
Everything
returns fine from this join as expected. However, there are cases where
there isn?t data for a given polygon and this return as the expected null
in the result set. I would like to utilize something like a case statement
to catch the nulls and return a ?more friendly? message. I have tried
unsuccessfully to use the following logic:

*Select case value_of_interest null then ?more friendly message? else
value_of_interest end*

*From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id*

If someone could let me know where I am going wrong it would be greatly
appreciated.

Cheers,

Derek

[Matheus de Oliveira]

Try that:

SELECT address, CASE WHEN value_of_interest IS NULL THEN 'more friendly
message' ELSE value_of_interest END value_of_interest
From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id


--
Matheus de Oliveira

Post by John Morgan
Hello,
I am doing a left outer join between a polygon table and a data table.
Everything
returns fine from this join as expected. However, there are cases where
there isn?t data for a given polygon and this return as the expected null
in the result set. I would like to utilize something like a case statement
to catch the nulls and return a ?more friendly? message. I have tried
*Select case value_of_interest null then ?more friendly message? else
value_of_interest end*
*From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id*
If someone could let me know where I am going wrong it would be greatly
appreciated.
Cheers,
Derek

[Matheus de Oliveira]

Even better:

SELECT COALESCE(value_of_interest, 'more friendly message')
value_of_interest
From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id

--
Matheus de Oliveira




On Fri, Feb 3, 2012 at 1:05 PM, Matheus de Oliveira <

Post by Matheus de Oliveira
SELECT address, CASE WHEN value_of_interest IS NULL THEN 'more friendly
message' ELSE value_of_interest END value_of_interest
From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id
--
Matheus de Oliveira

Post by John Morgan
Hello,
I am doing a left outer join between a polygon table and a data table.
Everything
returns fine from this join as expected. However, there are cases where
there isn?t data for a given polygon and this return as the expected null
in the result set. I would like to utilize something like a case statement
to catch the nulls and return a ?more friendly? message. I have tried
*Select case value_of_interest null then ?more friendly message? else
value_of_interest end*
*From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id*
If someone could let me know where I am going wrong it would be greatly
appreciated.
Cheers,
Derek

[jdmorgan]

Thanks Matheus. The coalesce method worked like a champ.

Cheers,
Derek

Post by Matheus de Oliveira
SELECT COALESCE(value_of_interest, 'more friendly message')
value_of_interest
From poly_table left outer join data_table one poly_table.common_id =
data_table.common_id
--
Matheus de Oliveira
On Fri, Feb 3, 2012 at 1:05 PM, Matheus de Oliveira
SELECT address, CASE WHEN value_of_interest IS NULL THEN 'more
friendly message' ELSE value_of_interest END value_of_interest
From poly_table left outer join data_table one
poly_table.common_id = data_table.common_id
--
Matheus de Oliveira
Hello,
I am doing a left outer join between a polygon table and a data table.
Everything
returns fine from this join as expected. However, there are cases where
there isn?t data for a given polygon and this return as the expected null
in the result set. I would like to utilize something like a case statement
to catch the nulls and return a ?more friendly? message. I have tried
*Select case value_of_interest null then ?more friendly message? else
value_of_interest end*
*From poly_table left outer join data_table one
poly_table.common_id =
data_table.common_id*
If someone could let me know where I am going wrong it would be greatly
appreciated.
Cheers,
Derek