-- Set these from the data you use in the insert of creature
SET
@NPC_CLASS := `unit_class`,
@NPC_LEVEL := ROUND((minlevel+maxlevel)/2, 0),
@EXP := `exp`;

-- Gets the base hp according to level, class and exp
SET
@GET_HP_COL :=
(SELECT CASE @EXP
    WHEN 0 THEN (SELECT basehp0 FROM creature_classlevelstats WHERE `level` = @NPC_LEVEL AND `class` = @NPC_CLASS)
    WHEN 1 THEN (SELECT basehp1 FROM creature_classlevelstats WHERE `level` = @NPC_LEVEL AND `class` = @NPC_CLASS)
    WHEN 2 THEN (SELECT basehp2 FROM creature_classlevelstats WHERE `level` = @NPC_LEVEL AND `class` = @NPC_CLASS)
END);

-- The generated NPC sql
INSERT INTO `creature_template` (`entry`, `difficulty_entry_1`, `difficulty_entry_2`, `difficulty_entry_3`, `KillCredit1`, `KillCredit2`, `modelid1`, `modelid2`, `modelid3`, `modelid4`, `name`, `subname`, `IconName`, `gossip_menu_id`, `minlevel`, `maxlevel`, `exp`, `faction`, `npcflag`, `speed_walk`, `speed_run`, `scale`, `rank`, `dmgschool`, `BaseAttackTime`, `RangeAttackTime`, `BaseVariance`, `RangeVariance`, `unit_class`, `unit_flags`, `unit_flags2`, `dynamicflags`, `family`, `trainer_type`, `trainer_spell`, `trainer_class`, `trainer_race`, `type`, `type_flags`, `lootid`, `pickpocketloot`, `skinloot`, `resistance1`, `resistance2`, `resistance3`, `resistance4`, `resistance5`, `resistance6`, `spell1`, `spell2`, `spell3`, `spell4`, `spell5`, `spell6`, `spell7`, `spell8`, `PetSpellDataId`, `VehicleId`, `mingold`, `maxgold`, `AIName`, `MovementType`, `InhabitType`, `HoverHeight`, `HealthModifier`, `ManaModifier`, `ArmorModifier`, `DamageModifier`, `ExperienceModifier`, `RacialLeader`, `questItem1`, `questItem2`, `questItem3`, `questItem4`, `questItem5`, `questItem6`, `movementId`, `RegenHealth`, `mechanic_immune_mask`, `flags_extra`, `ScriptName`, `VerifiedBuild`)
VALUES (50000, 0, 0, 0, 0, 0, 169, 11686, 0, 0, 'Orb Rotation Focus (3)', '', '', 0, 80, 80, 0, 14, 0, 2.2, 0.785714, 1, 0, 0, 2000, 2000, 1, 1, 1, 33554688, 2048, 0, 0, 0, 0, 0, 0, 10, 1048576, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '', 0, 3, 1, (@NPC_HEALTH/@GET_HP_COL), 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 118, 1, 0, 128, '', 12340);