Using Lateral - Mailing list pgsql-general

From Johann Spies
Subject Using Lateral
Date
Msg-id CAGZ55DR4DOTr+=hdUeM3C5_sqN1ARdgYbfX7W3PbkvBO+UfvCg@mail.gmail.com
Whole thread Raw
Responses Re: Using Lateral  (Paul Jungwirth <pj@illuminatedcomputing.com>)
Using Lateral  ("David G. Johnston" <david.g.johnston@gmail.com>)
List pgsql-general
In the past I could use this in a query:

    SELECT
        DISTINCT ut,
        CASE
            WHEN xpath_exists ('//t:address_spec/t:country/text()',
                q.address_spec,
                p.ns)
            THEN unnest (xpath ('//t:address_spec/t:country/text()',
                    q.address_spec,
                    p.ns))::citext
            ELSE NULL
        END country,

No longer.  The error message suggests I should use a lateral query.
But I could not figure out in the documentation how to get the same
result using a "lateral" construct.

Just selecting "unnest(...)" gives the wrong result because if the
xpath does not exist all the other parts of the query (like 'ut' in
this case) also are empty.

Regards
Johann

-- 
Because experiencing your loyal love is better than life itself,
my lips will praise you.  (Psalm 63:3)


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