Clever Geek Handbook

Query using CASE WHEN

I am trying to write a query like this and I am getting an error. This is my first use case, so I believe there will be a problem.

UPDATE my_table 
       CASE
              WHEN downloads IS NULL THEN 
              SET    downloads = 1 
              ELSE 
              SET    downloads + 1 
       END
WHERE  attachment_id = 8990 
AND    parent_post_id = 9221 
OR     attachment_id = 9211 
AND    parent_post_id = 383
+3


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2 answers


You can rewrite it below

UPDATE my_table 
SET downloads = CASE WHEN downloads IS NULL THEN  1 
                ELSE downloads + 1 END
WHERE attachment_id = 8990 
AND (parent_post_id = 9221 
OR attachment_id = 9211 )
AND parent_post_id = 383


Also you need to group your condition or

in ()

to match 9211

against parent_post_id

and attachment_id

using or operation, also confusing conditions that you have in your query arise like parent_post_id

it attachment_id

can be equal to 2 values ​​at the same time, maybe you are looking for

WHERE (attachment_id = 8990  AND parent_post_id = 9221 ) 
OR (attachment_id = 9211  AND parent_post_id = 383)
+5


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Syntax

update

- update table set col=value where condition

. Usage case

doesn't change this. case

can only be used to express an expression, so:



UPDATE my_table 
SET    downloads = CASE WHEN downloads IS NULL THEN 1 ELSE downloads + 1 END 
WHERE  attachment_id = 8990 AND
       parent_post_id = 9221 OR
       attachment_id = 9211 AND 
       parent_post_id = 383
+1


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