【SpatiaLite】2頂点からなるLINESTRINGの頂点座標を求める

-- 2頂点p1(x1, y1), p2(x2, y2)を結ぶ線分（LINESTRING)の頂点座標を求める。
SELECT
    X(p1) AS x1,
    Y(p1) AS y1,
    X(p2) AS x2,
    Y(p2) AS y2
FROM
(
    SELECT
        PointN(geom, 1) AS p1,
        PointN(geom, 2) AS p2
    FROM
    (
        SELECT
            GeomFromText('LINESTRING(0 1, 2 3)', 0) AS geom
    )
)

GeomFromText('LINESTRING(0 1, 2 3)', 0)のところを任意のLINESTRINGジオメトリで置き換えればOKです。