Cast till decimal bör hjälpa :-
mysql> select cast( "5.89872212195226e-05" as decimal(65,30)); +--------------------------------------------------+ | cast( "5.89872212195226e-05" as decimal(65,30)) | +--------------------------------------------------+ | 0.000058987221219522600000000000 | +--------------------------------------------------+
Exempel på jämförelse :-
mysql> select least( 4, cast("5.89872212195226e-05" as decimal(65,30)) );
+------------------------------------------------------------+
| least( 4, cast("5.89872212195226e-05" as decimal(65,30)) ) |
+------------------------------------------------------------+
| 0.000058987221219522600000000000 |
+------------------------------------------------------------+
Exempel på användning :-
MIN(cast( ... as decimal(65,30)))