我运行以下mysql查询，并在第一个查询中看到类型为ALL。
mysql> EXPLAIN
SELECT one.language_id as filter_id,
one.language_name as filter_name,
two.count as count
FROM books_f9_languages one
INNER JOIN (SELECT language_id,
count(*) as count
FROM link_f9_books_lists
WHERE books_list_id IN (1691,1,2,3,4,6,7,8,9,10,11,12,13,14,17,18,19,20,21,22,23,24,25,26,28,29,30,31,32,33,34,35,36,37,43,44,47,51,54,57,58,59,68,71,76,77,86,88,93,94,99,120,125,126,127,133,146,147,148,257,260,261,262,263,264,266,267,268,269,270,271,272,275,276,286,767,768,769,771,772,774,777,779,783,785,786,790,792,799,808,811,813,814,815,819,825,828,829,847,850,852,853,855,856,857,858,862,863,866,869,873,875,882,891,900,907,917,925,930,935,1092,1531,1532,1533,1534,1535,1536,1537,1538,1540,1541,1542,1543,1544,1545,1546,1547,1548,1549,1550,1551,1552,1553,1554,1556,1557,1558,1560,1561,1563,1564,1565,1567,1568,1569,1570,1571,1572,1574,1575,1576,1577,1578,1579,1580,1581,1582,1583,1584,1586,1588,1589,1590,1591,1592,1595,1597,1599,1600,1601,1603,1604,1605,1606,1607,1608,1609,1610,1612,1613,1614,1615,1616,1617,1620,1621,1622,1623,1624,1625,1627,1628,1629,1630,1632,1636,1637,1638,1639,1640,1642,1643,1644,1645,1646,1648,1649,1651,1652,1653,1654,1659,1660,1662,1665,1675,1677,1679,1680,1689,1692,1693,1696,1698,1699,1702,1703,1705,1711,1713,1714,1716,1717,1719,1720,1726,1728,1729,1732,1734,1735,1736,1738,1743,1744,1753,1754,1755,1756,1759,1786,1787,1788,1789,1790,1791,1792,1793,1794,1795,1797,1837,827) GROUP BY language_id) two
WHERE one.language_id = two.language_id
ORDER BY filter_name;
这是输出，
+----+-------------+---------------------+--------+---------------+---------------+---------+-----------------+------+-----------------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+---------------------+--------+---------------+---------------+---------+-----------------+------+-----------------------------------------------------------+
| 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 5 | Using temporary; Using filesort |
| 1 | PRIMARY | one | eq_ref | PRIMARY | PRIMARY | 4 | two.language_id | 1 | |
| 2 | DERIVED | link_f9_books_lists | range | books_list_id | books_list_id | 4 | NULL | 273 | Using where; Using index; Using temporary; Using filesort |
+----+-------------+---------------------+--------+---------------+---------------+---------+-----------------+------+-----------------------------------------------------------+
3 rows in set (0.01 sec)
我必须索引哪一列才能生成ALL，请使用索引。
感谢。
答案 0 :(得分：1)
派生的临时表不能使用索引。
删除ORDER BY子句或按language_id排序应该解决这个问题。
或者，您可以尝试在books_f9_languages表上的language_id和language_name上添加复合索引。
要改进内部查询，请在book_list_id和language_id上为link_f9_books_lists表添加复合索引。