SQL中的if语句来计算年龄

Question

I am very new at SQL and I have been working on my First Query. Now I need your help. I have this report in Excel. I have formula in the AGE column N calculating the AGE. I have been trying to create a SQL query to come up with the same answer. So far I have figured out the columns that I need and pulled all the data to Match Excel. Only thing is I don't know how and where to enter this IF statement so it will calculate the age when i run the query.

Work Order  Location    MISC    Status  Actual Finish   Finish Time Parent WO   Work Type   N   Reported Date   Reported Time   Site    Gen Age Sub Name    Substation Location                         
1234567899  4074        COMP    11/5/14 3:08:49 PM      CM      10/7/14 1:47:42 PM          29.05633102                                 
12348574987 2946        SCHED               CM      10/30/14    10:28:03 AM         188.5638542     

AGE is a formula, pasted below:

=IF ((IF(Status<>"Comp",Today()-Reported date, actual finish-reported date))<0,0, IF(STATUS<>"COMP", TODAY()-REPORTED DATE, ACTUAL FINISH-REPORTED DATE))       

SQL Writen Query

SELECT WO.WONUM,                                                                                        
  LOCOFFDESC.DESCRIPTION AS OFFICE,                                                                                     
  WO.STATUS,                                                                                        
  WO.LOCATION,                                                                                      
  CASE                                                                                      
    WHEN ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) = 0)                                                                                        
    THEN SUBSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2)), LENGTH(LOCOFF.EXT_LOC_HIERARCHY_PATH))                                                                                      
    WHEN ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) IS NOT NULL)                                                                                        
    THEN SUBSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2)), (INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) - (INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2))                                                                                      
  END AS "SUBSTATION CASE",                                                                                     
  WO.PARENT,                                                                                        
  WO.WORKTYPE,                                                                                      
  WO.REPORTEDBY,                                                                                        
  WO.REPORTDATE,                                                                                        
  WO.ACTFINISH,                                                                                     
  WO.SITEID                                                                                     
FROM LOCATIONS LOCOFF                                                                                       
RIGHT JOIN MAXPRD.WORKORDER WO                                                                                      
ON WO.LOCATION = LOCOFF.LOCATION                                                                                        
INNER JOIN MAXPRD.LOCANCESTOR LOCOFFANC                                                                                     
ON LOCOFFANC.LOCATION = LOCOFF.LOCATION                                                                                     
INNER JOIN MAXPRD.LOCATIONS LOCOFFDESC                                                                                      
ON LOCOFFANC.ANCESTOR = LOCOFFDESC.LOCATION                                                                                     
INNER JOIN MAXPRD.LOCHIERARCHY LOCOFFHIER                                                                                       
ON LOCOFFANC.ANCESTOR = LOCOFFHIER.LOCATION                                                                                     
WHERE LOCOFF.SITEID   = 'SUB'                                                                                       
AND LOCOFFHIER.PARENT = '2000'                                                                                      
GROUP BY WO.WONUM,                                                                                      
  LOCOFFDESC.DESCRIPTION,                                                                                       
  WO.STATUS,                                                                                        
  WO.LOCATION,                                                                                      
  LOCOFF.EXT_LOC_HIERARCHY_PATH,                                                                                        
  LOCOFF.SITEID,                                                                                        
  LOCOFFHIER.PARENT,                                                                                        
  WO.PARENT,                                                                                        
  WO.WORKTYPE,                                                                                      
  WO.REPORTEDBY,                                                                                        
  WO.REPORTDATE,                                                                                        
  WO.ACTFINISH,                                                                                     
  WO.SITEID 

Answer 1

You place the calculation after the SELECT statement, before the FROM statement, so you have a column filled with calculated values, similar to excel.

We need to know what database system you are working with to get the exact syntax. Can you try after WO.SITEID,

SELECT WO.WONUM,
  LOCOFFDESC.DESCRIPTION AS OFFICE,
  WO.STATUS,
  WO.LOCATION,
  CASE
    WHEN ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) = 0)
    THEN SUBSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2)), LENGTH(LOCOFF.EXT_LOC_HIERARCHY_PATH))
    WHEN ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) IS NOT NULL)
    THEN SUBSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, ((INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2)), (INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 2, 3)) - (INSTR(LOCOFF.EXT_LOC_HIERARCHY_PATH, '/', 1, 2) + 2))
  END AS "SUBSTATION CASE",
  WO.PARENT,
  WO.WORKTYPE,
  WO.REPORTEDBY,
  WO.REPORTDATE,
  WO.ACTFINISH,
  WO.SITEID,
 (
CASE 
    WHEN (
        CASE WHEN WO.STATUS != 'Comp'
            THEN SYSDATE-WO.REPORTDATE
            ELSE WO.ACTFINISH-WO.REPORTDATE
        END) < 0
        THEN 0
        ELSE
            CASE WHEN STATUS != 'COMP'
                THEN SYSDATE-WO.REPORTDATE
                ELSE WO.ACTFINISH-WO.REPORTDATE
            END
END) as age
FROM LOCATIONS LOCOFF
RIGHT JOIN MAXPRD.WORKORDER WO
ON WO.LOCATION = LOCOFF.LOCATION
INNER JOIN MAXPRD.LOCANCESTOR LOCOFFANC
ON LOCOFFANC.LOCATION = LOCOFF.LOCATION
INNER JOIN MAXPRD.LOCATIONS LOCOFFDESC
ON LOCOFFANC.ANCESTOR = LOCOFFDESC.LOCATION
INNER JOIN MAXPRD.LOCHIERARCHY LOCOFFHIER
ON LOCOFFANC.ANCESTOR = LOCOFFHIER.LOCATION
WHERE LOCOFF.SITEID   = 'SUB'
AND LOCOFFHIER.PARENT = '2000'
GROUP BY WO.WONUM,
  LOCOFFDESC.DESCRIPTION,
  WO.STATUS,
  WO.LOCATION,
  LOCOFF.EXT_LOC_HIERARCHY_PATH,
  LOCOFF.SITEID,
  LOCOFFHIER.PARENT,
  WO.PARENT,
  WO.WORKTYPE,
  WO.REPORTEDBY,
  WO.REPORTDATE,
  WO.ACTFINISH,
  WO.SITEID

Edited for MS SQL server. Edited AGAIN for Oracle :)