The command syntax with which mysql table can be repaired is as follows:
REPAIR TABLE tablename;
REPAIR TABLE tablename QUICK;
REPAIR TABLE tablename EXTENDED;
The command will just do as it says repair a specified table, but if QUICK or EXTENDED is used then the meaning of it changes. In case of QUICK it will repair only the index tree, whereas in case of EXTENDED it will create index row by row and repair it.