mysql - SQL 从一个表中选择两次与单个表相关的字段

Question

我有 2 张桌子

--------------------------------------------
TABLE 1:
ID
DUREE_FREQ_ID => foreign key idFrequence
POSOL_FREQ_ID => foreign key idFrequence
INTER
------------------------------------------
TABLE 2:
idFrequence
libFrequence
-------------------------------------------

我想同时查询libFrequence和DUREE_FREQ_ID获取POSOL_FREQ_ID！

Answer 1

SELECT Table1.*, t2a.libFrequence AS DUREElib, t2b.libFrequence AS POSOLlib
FROM Table1
INNER JOIN Table2 AS t2a ON Table1.DUREE_FREQ_ID = t2a.idFrequence
INNER JOIN Table2 AS t2b ON Table1.POSOL_FREQ_ID = t2b.idFrequence

Answer 2

SELECT
  t1.id,
  t1.duree_freq_id,
  td.libfrequence AS duree_freq,
  t1.posol_freq_id,
  tp.libfrequence AS posol_freq
FROM table1 t1
LEFT JOIN table2 td ON (td.idfrequence = t1.duree_freq_id)
LEFT JOIN table2 tp ON (tp.idfrequence = t1.posol_freq_id);