教你快速掌握Oracle SQL到DB2 SQL的移植

WHEN 条件 THEN 结果1 

ELSE 结果2 

END

WHEN 表达式2 THEN 结果1 

ELSE 结果2 

END

SELECT ORDNO,CUSNO, 

CASE MONTH(SHIPDATE) 

WHEN ''01'' THEN ''Jan'' 

WHEN ''02'' THEN ''Feb'' 

WHEN ''03'' THEN ''Mar'' 

WHEN ''04'' THEN ''Apr'' 

WHEN ''05'' THEN ''May'' 

WHEN ''06'' THEN ''Jun'' 

WHEN ''07'' THEN ''Jul'' 

WHEN ''08'' THEN ''Aug'' 

WHEN ''09'' THEN ''Sep'' 

WHEN ''10'' THEN ''Oct'' 

WHEN ''11'' THEN ''Nov'' 

WHEN ''12'' THEN ''Dec'' 

END 

FROM FILE 

应用实例： 

Oracle SQL： 

------------------------- 

select decode(t.organtypecode, ''D'', t.parent, ''S'', t.parent, t.id) 

from A_ORGAN t 

where t.parent = 35 

DB2 SQL： 

------------------------- 

select case x.organtypecode 

when ''D'' then 

x.parent 

when ''S'' then 

x.parent 

else 

x.id 

end 

from a_Organ x 

where x.parent = 35;