Help me to understand the case statements in this query

[nc297]

Can someone tell me what these two case statements are doing please.

SELECT c.officecode AS doc,
CASE
WHEN typecode IN ( 1, 18 ) THEN reportsto
WHEN typecode IN ( 13 ) THEN officecode
ELSE NULL
END AS dist,
c.region AS reg, r.regionacronym,
CASE
WHEN area < 10 THEN '0' + CAST(area AS CHAR(1))
ELSE CAST(area AS CHAR(2))
END AS area,
REPLACE(c.name, ',', '') AS doc_name,
r.regionnumber AS region_num, r.regionname,
c.typecode
FROM offices.dbo.officecodes AS c
INNER JOIN offices.dbo.regions AS r
ON c.region = r.regionletter
WHERE ( c.typecode IN ( 1, 18, 13 ) )

 

[simian336]

WHEN typecode IN ( 1, 18 ) THEN reportsto

if typecode is 1 or 18 then give me column reportsto
otherwise

WHEN typecode IN ( 13 ) THEN officecode

if typecode is 13 then give me column officecode

ELSE NULL

otherwise give me nothing.

simi

 

[nc297]

Thanks so much Simian I understand it now. One can you explain this one to me:

CASE WHEN area < 10 THEN '0' + CAST(area AS CHAR(1)) ELSE CAST(area AS CHAR(2)) END AS area,

 

[hopper44]

When area is less than 10 (i.e. 0-9), then output with a preceding 0. For example, if area = 4, then output '04'.

Otherwise, output area as two characters (e.g. if area=25, it will output '25').

This assumes that area will be 0 through 99.
If it is greater than two digits, results will be undefined.