优化5个内连接

SELECT *
FROM TableA
INNER JOIN TableB ON TableA.id = TableB.a_id
INNER JOIN TableC ON TableB.id = TableC.b_id
INNER JOIN TableD ON TableC.id = TableD.c_id
INNER JOIN TableE ON TableD.id = TableE.d_id;

-- 使用索引
CREATE INDEX idx_tablea_id ON TableA(id);
CREATE INDEX idx_tableb_a_id ON TableB(a_id);
CREATE INDEX idx_tablec_b_id ON TableC(b_id);
CREATE INDEX idx_tabled_c_id ON TableD(c_id);
CREATE INDEX idx_tablee_d_id ON TableE(d_id);

-- 使用子查询或CTE
WITH CTE AS (
    SELECT *
    FROM TableA
    INNER JOIN TableB ON TableA.id = TableB.a_id
)
SELECT *
FROM CTE
INNER JOIN TableC ON CTE.b_id = TableC.b_id
INNER JOIN TableD ON TableC.id = TableD.c_id
INNER JOIN TableE ON TableD.id = TableE.d_id;