I work on two terminals only on command lines (phpmyadmin is not used here):
-MariaDB 10.1.9 (on the first computer running Windows 10)
-Mysql 5.1.73 (on the second computer running Windows 10)
I run this special command:
SELECT price, volume
FROM dates d
LEFT JOIN (
SELECT fr.price,fr.volume,f.code_pays,fr.flux,fr.id_date, cf.code,fr.niv
FROM fr_logical_data_2 fr
INNER JOIN fr_pays f ON fr.id_code_pays = f.id
INNER JOIN fr_nc8 n ON fr.id_code_nc8 = n.id
INNER JOIN commodities_fr cf ON n.code_nc8 = cf.nc8
WHERE cf.code = 'code_007' AND fr.flux= 1 AND f.code_pays = 'PT' AND fr.niv = 0
) AS Q
ON Q.id_date = d.id
Mysql requires: 0.1 s;
MariaDB requires: 4 min and 5 sec.
Exact result (49 lines), the result of the query below
Note. Two computers usually have the same response time
2: LEFT JOIN INNER JOIN ( , , ). , , MariaDB LEFT RIGHT JOINs.
- ?
3: EXPLAIN SELECT... EXPLAIN SELECT...