存儲程序的CASE語句實現(xiàn)一個復雜的條件構造。如果search_condition?求值為真，相應的SQL被執(zhí)行。如果沒有搜索條件匹配，在ELSE子句里的語句被執(zhí)行。

CASE?case_value??

WHEN?when_value?THEN?statement_list??

[WHEN?when_value?THEN?statement_list]?...??

[ELSE?statement_list]??

END?CASE??

Or:??

CASE??

WHEN?search_condition?THEN?statement_list??

[WHEN?search_condition?THEN?statement_list]?...??

[ELSE?statement_list]??

END?CASE