游标的声明应该在创建临时表之前
我还取消了在临时表中插入代码的注解

DECLARE rowCount INT Default 0;
    DECLARE counter INT Default 0;
    DECLARE WID char(6);
    DECLARE WType_WTID varchar(15);
    DECLARE WUID char(6);
    DECLARE BattleGroup char(5);
    DECLARE CubicAreaWeight decimal(10,2);
    DECLARE FuelCapacity decimal(10,2);
    DECLARE FuelExpenditure_Mile decimal(10,2);
    DECLARE ArmorWeight decimal(10,2);
    DECLARE StructureWeight decimal(10,2);
    DECLARE Status VARCHAR(20);
    DECLARE CostToRepair int(10);

    DECLARE walkerMaster CURSOR FOR
     SELECT IWA.WID, concat(IWA.WalkerType, " - ", IWT.WTypeID) AS WType_WTID
     , IWA.WUID, WU.BattleGroup, walkerCubicAreaWeight(IWA.WalkerType) AS 
     CubicAreaWeight, walkerFuelCapacity(IWA.WalkerType) AS FuelCapacity
     ,walkerFuelExpenditure(IWA.WalkerType) AS FuelExpenditure_Mile, 
      walkerArmorWeight(IWA.WalkerType) AS ArmorWeight
      ,walkerStructureWeight(IWA.WalkerType) AS StructureWeight, IWA.Status
      , CASE  WHEN IWA.Status = 'Damaged' AND IWA.WalkerType = 'AT-AT' THEN 122 
      * IWT.Weight 
        WHEN IWA.Status = 'Damaged' AND IWA.WalkerType = 'AT-ST' THEN 89 * 
      IWT.Weight
            ELSE 0 END AS CostToRepair
     FROM imperial_walkers_assign IWA
     LEFT JOIN imperial_walker_type IWT ON IWA.WalkerType = IWT.WType
     LEFT JOIN walker_units WU ON IWA.WUID=WU.WUID
    ORDER BY IWA.WID;

    DROP temporary table walker_master;

    CREATE temporary table walker_master(
        WID char(6),
    WType_WTID varchar(15),
    WUID char(6),
    BattleGroup char(5),
    CubicAreaWeight decimal(10,2),
    FuelCapacity decimal(10,2),
    FuelExpenditure_Mile decimal(10,2),
    ArmorWeight decimal(10,2),
    StructureWeight decimal(10,2),
    Status VARCHAR(20),
    CostToRepair int(10)
    );

    OPEN walkerMaster;
      BEGIN
    SELECT Found_Rows() INTO rowCount;
    process_loop : loop
     IF counter < rowCount THEN
     FETCH walkerMaster INTO WID ,WType_WTID, WUID, BattleGroup, 
     CubicAreaWeight, FuelCapacity,
     FuelExpenditure_Mile, ArmorWeight, StructureWeight,Status, CostToRepair;

    insert into walker_summary (WID,WType_WTID,WUID,BattleGroup,CubicAreaWeight,FuelCapacity,FuelExpenditure_Mile,ArmorWeight,StructureWeight,
    StructureWeight,Status,CostToRepair)
    SELECT WID ,WType_WTID,WUID, 
     BattleGroup, CubicAreaWeight, FuelCapacity,
     FuelExpenditure_Mile, ArmorWeight, StructureWeight,Status, CostToRepair;
     SELECT WID ,WType_WTID, WUID, BattleGroup, CubicAreaWeight, FuelCapacity,
     FuelExpenditure_Mile, ArmorWeight, StructureWeight,Status, CostToRepair;
     SET counter = counter +1;
     ELSE
     leave process_loop;
    END IF;
    END loop process_loop;
    END;
    CLOSE walkerMaster;

    END