Creating MySQL View using UNION

Question

I am trying to create a view for the following query.

SELECT DISTINCT
  products.pid        AS id,
  products.pname      AS name,
  products.p_desc     AS description,
  products.p_loc      AS location,
  products.p_uid      AS userid,
  products.isaproduct AS whatisit
FROM products
UNION
SELECT DISTINCT
  services.s_id       AS id,
  services.s_name     AS name,
  services.s_desc     AS description,
  services.s_uid      AS userid,
  services.s_location AS location,
  services.isaservice AS whatisit
FROM services

But not able to do so. I am using MySql query browser. The error I am getting is:

A view can only be created from an active resultset of SELECT command

Can someone please help me with this?

Solution 1

You might want to swith the order of userid and location in the second select. The column names should match 1 to 1 in all selects of the union.

EDIT : For query browser , as this points out "To create a view from a query, you must have executed the query successfully. To be more precise, the view is created from the latest successfully executed query, not necessarily from the query currently in the Query Area"

so you need to execute the query first before you create the view in query browser.

The error is from the query browser and not mysql.

Solution 2

You have different types being unioned into the same column. (The names can be different, but the types have to be the same, or at least auto-castable.) But as @Learning points out, it looks like you've twisted the SELECT column enumerations.

Just in case, the proper syntax (which worked for me) is

CREATE VIEW myView 
AS  
SELECT ... 

Comments

[Learning]

if column names are different what column name would be reported when we do a select * from the view?

[dkretz]

The first one. Try it and see (which is what I did.)

[Admin]

The UNION part is working fine.. But I when I try to create a view for this UNION. I'm getting the following error: A view can only be created from an active resultset of SELECT command I amd using MySql query browser

[Learning]

oh .. ok. Sybase is less forgiving. Thanks for the clarification.

[dkretz]

Are you able to create a view at all? Try it with just "CREATE VIEW vWhatever AS SELECT pid FROM products" and work forward from there.

[dkretz]

@Learning, are you trying these suggestions? I didn't need to execute the query first. I executed some other query, then executed "CREATE VIEW ... " and it worked fine.

[dkretz]

OK, just add pieces from there until you know which part makes it fail.

[Learning]

no I'm not. I do not have access to mysql. I'm just trying to help.

[dkretz]

Your link suggests you might be right - I don't have that query browser, but it works ok in sqlyog.