Re: [gnome-db] GdaSqlBuiler: JOIN AS



On 17.05.2010, at 16:53, Murray Cumming wrote:

> Here's a silly example that shows the need for the name, because using
> the table name would be ambiguous:
> 
> SELECT "albums"."album_id", "albums"."name",
> "albums"."artist_singer_id", "relationship_artist_singer"."name",
> "albums"."artist_drummer_id", "relationship_artist_drummer"."name",
>  FROM "albums"
>  LEFT JOIN "artists"
>    AS "relationship_artist_singer"
>    ON ("albums"."artist_singer_id" =
> "relationship_artist_singer"."artist_id")
>  LEFT JOIN "artists"
>    AS "relationship_artist_drummer"
>    ON ("albums"."artist_drummer_id" =
> "relationship_artist_drummer"."artist_id")
> WHERE "albums"."album_id" = 123

Vivien says, that you are setting alias not for join, but for table, which is joined.
Better illustrated by different formatting:

FROM
    "albums"
LEFT JOIN
    "artists" AS "relationship_artist_singer"
    ON ("albums"."artist_singer_id" = "relationship_artist_singer"."artist_id")
LEFT JOIN
    "artists" AS "relationship_artist_drummer"
    ON ("albums"."artist_drummer_id" = "relationship_artist_drummer"."artist_id")


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