[OT] SQL-question

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Hi,

i know I'm slightly off topic, but I don't know where else to ask. I
have a little SQL-question abaut a linking table. I have the following
tables:

CREATE TABLE Person (
~  id serial PRIMARY KEY
~  name text,
~  ...
);

CREATE TABLE Relations (
~  is integer REFERENCES Person,
~  rel char(7) CHECK ( rel == 'partner' OR ... ),
~  of integer REFERENCES Person,
~  CONSTRAINT Relations_pkey PRIMARY KEY ( is, rel )
);

Now I would like to make a query to the Relations table asking if some
'person' is the partner of another, and get the id of the partner. How
would the SQL look like if I just have the row (1 is partner of 2) and
not the row (2 is partner of 1) in the Relations table?

Thanks in advance.

- --
Grüße,

Andreas Fromm

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