Using case pull infor from one of two columns

Question

how can I use the case statement to pull data from rows that are grouped together from a table? or is there a way to use if..then?
my incorrect , unfinished query.....
select t1.col1 from tab1 t1,tab2 t2
where
t1.col1= t2.col1 and
t1.col1= < if I find an 'x' in t2.col2 then return all t1 rows from that group that have x's in corresponding t2.col2
else return all rows that have an x's in corresponding t2.col3>
group by t1.col1

Answer 1

One table has data like this:
STG_CLAIMANT_XREF
SRC_EVENT_NUMBER     SRC_CLAIM_NUMBER     SRC_CLMT_NO     STG_CLAIM_TYPE
0040283362              00402833620001                 0001          112
0040283362              00402833620002                 0002          111
0040283362              00402833620003                 0003          112
0040283362              00402833620050                 0050          115The above represents one group of data from a group by SRC_EVENT_NUMBER,
a subset of groups from the whole table.
The other has data like this:
CLAIMTYPE_X_BI_PD
CODE_ID     PD_TYPE     BI_TYPE
110       -1     
111            -1
112       -1     
119            -1I want to run through the 1st table and match the STG_CLAIM_TYPEs to the CODE_IDs
in the second table.
I'm going to join STG_CLAIM_TYPE = CODE_ID.
If ANY rows in the first table have STG_CLAIM_TYPEs with values in the PD_TYPE col in the second table than for that group I can ONLY return the rows that have STG_CLAIM_TYPEs = 111 for example.
However, if No rows of type 111 exist but rows STG_CLAIM_TYPEs = 111 exist (STG_CLAIM_TYPEs with values in the BI_TYPE col) Than I can only return rows that have STG_CLAIM_TYPEs = 112
my first try was a query that worked but returned both type out of each group. It was
select xr.SRC_EVENT_NUMBER, xr.SRC_CLAIM_NUMBER, xr.STG_CLAIM_TYPE
from STG_CLAIMANT_XREF xr, CLAIMTYPE_X_BI_PD BP
where
xr.STG_CLAIM_TYPE = bp.CODE_ID
and
(bp.PD_TYPE = -1 or bp.BI_TYPE = -1)
group by xr.SRC_EVENT_NUMBER, xr.SRC_CLAIM_NUMBER, xr.STG_CLAIM_TYPE;
will return rows 1,2,& 3. I need only 1 & 3 or just 2.
I figured using a case statement would help me solve this issue but I am usure of how to
implement it.
What would you suggest?
Message was edited by:
user623359