SSRS: Using exists condition in sql where clause while passing values from SSRS Parameter

Question

Table : incident
----------------
incident_id   usr_id    item_id   Inc_Date
10059926       191       61006    8-22-2015
10054444       222        3232    6-7-2015

Table: act_reg
--------------
 act_reg_id  act_type_id  incident_id    usr_id  act_type_sc
 454244         1        10059926         191    ASSIGN
 471938        115       10059926         191    TRAVEL TIME
 473379        40        10059926         191    FOLLOW UP
 477652        115       10059926         191    TRAVEL TIME
 489091        504       10059926         191    ADD_ATTCHMNTS
 477653        504       10054444         222    ADD_ATTCHMNTS

Parameter: @attach (value=1, Label=Yes & Value=0, Label=No)

 Result (While I am selecting 'Yes' in dropdown)
 ----------------------------------------------
 incident_id   usr_id    item_id  
 10059926       191      61006    
 10054444       222       3232

My Query:

SELECT  incident.incident_id,incident.usr_id,incident.item_id
FROM  incident 
where exists (select * from act_reg 
              where incident.incident_id = act_reg.incident_id
                  and act_reg.act_type_sc (case when @attach=1 and act_reg.act_type_sc='ADD_ATTCHMNTS' then NULL else act_reg.act_type_sc end  )
           )

Please help me on this.

Answer 1

You should change your query to the following :-

SELECT  incident.incident_id,incident.usr_id,incident.item_id
FROM  incident
left join act_reg 
on incident.incident_id = act_reg.incident_id and act_reg.act_type_sc = 'ADD_ATTCHMNTS'
where 
((@attach = 1 and act_reg.act_reg_id is not null) or 
(@attach = 0 and act_reg.act_reg_id is null))
group by incident.incident_id,incident.usr_id,incident.item_id

SQL Fiddle