我有问题是查询
SELECT *
FROM files f
LEFT JOIN xfiles x ON x.hash = f.bhash
LEFT JOIN cate c ON c.id = f.cate
LEFT JOIN users u ON u.id = f.user
LEFT JOIN userslev ul ON u.id_lev = ul.id
LEFT JOIN (
SELECT DISTINCT x.hash, s.iis
FROM anno x
JOIN seb s ON s.iis = x.icc
WHERE x.le =0
AND (
x.eve =0
OR x.eve =2
)
GROUP BY `x`.`hash`
) AS tabel2 ON tabel2.hash = f.bhash
WHERE f.see + IFNULL( x.see, 0 ) + f.lee + IFNULL( x.lee, 0 ) >0
ORDER BY f.added DESC
显示第 0 - 29 行（总共 22,083 行，查询耗时 9.6523 秒）
如您所见，需要 9 秒！
但没有“订购”
SELECT *
FROM files f
LEFT JOIN xfiles x ON x.hash = f.bhash
LEFT JOIN cate c ON c.id = f.cate
LEFT JOIN users u ON u.id = f.user
LEFT JOIN userslev ul ON u.id_lev = ul.id
LEFT JOIN (
SELECT DISTINCT x.hash, s.iis
FROM anno x
JOIN seb s ON s.iis = x.icc
WHERE x.le =0
AND (
x.eve =0
OR x.eve =2
)
GROUP BY `x`.`hash`
) AS tabel2 ON tabel2.hash = f.bhash
WHERE f.see + IFNULL( x.see, 0 ) + f.lee + IFNULL( x.lee, 0 ) >0
显示第 0 - 29 行（总共 22,083 行，查询耗时 0.0241 秒）
只有 0.0241 秒 :)
…………
有没有办法让“订购”与美好时光？
…………
索引：
Indexes: (files)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No ihash 27815 A
Edit Drop filename BTREE No No filename 27815 A
Edit Drop cate BTREE No No cate 45 A
Edit Drop user BTREE No No user 1264 A
Edit Drop bhash BTREE No No bhash (20) 27815 A
Edit Drop added BTREE No No added 27815 A
Edit Drop filename_2 FULLTEXT No No filename 1
Indexes: (xfiles)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No id 8196 A
Edit Drop hash BTREE Yes No hash 8196 A
Edit Drop see BTREE No No see 37 A
Edit Drop leec BTREE No No lee25 A
Indexes: (cate)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No id 51 A
Indexes: (users)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No id 39776 A
Edit Drop username BTREE Yes No username 39776 A
Edit Drop id_lev BTREE No No id_lev 19 A
Indexes: (userslev)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop base BTREE Yes No id 22 A
Indexes: (anno)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No id 23636 A
Edit Drop icc BTREE No No icc 2626 A
Edit Drop eve BTREE No No eve 8 A
Edit Drop hash BTREE No No hash 5909 A
Edit Drop le BTREE No No le 875 A
Indexes: (seb)
Action Keyname Type Unique Packed Column Cardinality Collation Null Comment
Edit Drop PRIMARY BTREE Yes No id 58 A
Edit Drop iis BTREE Yes No iis 58 A YES
解释：
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY f ALL NULL NULL NULL NULL 27819 Using temporary; Using filesort
1 PRIMARY x eq_ref hash hash 20 f.bhash 1 Using where
1 PRIMARY c eq_ref PRIMARY PRIMARY 4 f.cate 1
1 PRIMARY u eq_ref PRIMARY PRIMARY 4 f.user 1
1 PRIMARY ul eq_ref base base 4 u.id_lev 1
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 1176
2 DERIVED s index iis iis 5 NULL 58 Using index; Using temporary; Using filesort
2 DERIVED x ref icc,eve,le icc 4 s.iis 9 Using where