php - USING SELECT CASE based on a constant value -

i have ff table called equipment:

+----------+----------+-----------+-------------+----------+---------+ | equip_id | chara_id | weapon_id | headgear_id | armor_id | ring_id | +----------+----------+-----------+-------------+----------+---------+ |        3 |        1 |         3 |           5 |        9 |       8 | |        5 |        3 |         3 |           5 |        3 |       8 | |        6 |        4 |         7 |           5 |        3 |       8 | |        7 |        5 |         4 |           5 |        3 |       8 | |        8 |        6 |         3 |           5 |        2 |       8 | |       10 |        8 |         3 |           5 |        2 |       8 | +----------+----------+-----------+-------------+----------+---------+ 

and have long case statement:

switch ($equip->item_type) {         case '1':             # weapon              $sql_equip = "update equipment set weapon_id = :item_id chara_id = :chara_id";               break;          case '2':             # armor             $sql_equip = "update equipment set armor_id = :item_id chara_id = :chara_id";             break;          case '3':             # ring             $sql_equip = "update equipment set ring_id = :item_id chara_id = :chara_id";             break;          case '4':             # headgear             $sql_equip = "update equipment set headgear_id = :item_id chara_id = :chara_id";             break;          default:             # nothing...             break;     } 

i saw queries on net can use case statements in queries, ive searched net , cant seem figure out correct 1 use.

i want in 1 statement since wrap on transact function , add line of mysql statement. instead of doing 4x2(current) 2(if done in 1 query) mysql queries.

you can have statement,

update  equipment  set     weapon_id = case when :itemtype = 1 :item_id else weapon_id end,         armor_id = case when :itemtype = 2 :item_id else armor_id end,         ring_id = case when :itemtype = 3 :item_id else ring_id end,         headgear_id = case when :itemtype = 4 :item_id else headgear_id end   chara_id = :chara_id 

but need pass 3 values, :itemtype, :item_id, :chara_id