is this a bug in PG 7? - Mailing list pgsql-admin

In PG 7.0.2, I have a select:

SELECT pr_category_id, pr_category_id FROM pr_category
    UNION SELECT pr_category_id, parent_cat FROM pr_category WHERE parent_cat
<> 0
    UNION SELECT pr_category_id, parent_cat_link FROM pr_category_link

when I run this I get a subset of the correct results. If I move the first
select to the end as in:

SELECT pr_category_id, parent_cat FROM pr_category WHERE parent_cat <> 0
    UNION SELECT pr_category_id, parent_cat_link FROM pr_category_link
    UNION SELECT pr_category_id, pr_category_id FROM pr_category

then it works correctly.

Any ideas? Is this a bug?


Thanks,


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