Subject Re: [firebird-support] How To Display Null Values At the End For More Than One Columns Specified in Order By Clause?
Author Vishal Tiwari
My sample SQL is as below:

Select T.EmpCode, EM.EmpName, 

Case When 
(Select <NumFieldName1> from TransactionTable T1 where T1.EmpCode = T.EmpCode And T1.CompCode = AVSP1.S_EarnCompCodeColumn1) Is Not Null Then 
S_EarnCompCodeColumn1 End As S_EarnCompCodeColumn1, 

(Select <NumFieldName1> from TransactionTable T1 where T1.Empcode = T.empcode And T1.CompCode = AVSP1.S_EarnCompCodeColumn1),

Case When 
(Select <NumFieldName1> from TransactionTable T2 where T2.EmpCode = T.EmpCode And T2.CompCode = AVSP1.S_EarnCompCodeColumn2) Is Not Null Then 
S_EarnCompCodeColumn2 End As S_EarnCompCodeColumn2, 

(Select <NumFieldName1> from TransactionTable T2 where T2.Empcode = T.empcode And T2.CompCode = AVSP1.S_EarnCompCodeColumn2),

Case When 
(Select <NumFieldName1> from TransactionTable T3 where T3.EmpCode = T.EmpCode And T3.CompCode = AVSP1.S_DedCompCodeColumn1) Is Not Null Then 
S_DedCompCodeColumn1 End As S_DedCompCodeColumn1, 

(Select <NumFieldName1> from TransactionTable T3 where T3.Empcode = T.empcode And T3.CompCode = AVSP1.S_DedCompCodeColumn1),

Case When 
(Select <NumFieldName1> from TransactionTable T4 where T4.EmpCode = T.EmpCode And T4.CompCode = AVSP1.S_DedCompCodeColumn2) Is Not Null Then 
S_DedCompCodeColumn2 End As S_DedCompCodeColumn2, 

(Select <NumFieldName1> from TransactionTable T4 where T4.Empcode = T.empcode And T4.CompCode = AVSP1.S_DedCompCodeColumn1),

from AVS_Payslip AVSP1 
Join TransactionTable T on AVSP1.S_EarnCompCodeColumn1 = T.CompCode 
join EmployeeMaster EM On EM.EmpCode = T.EmpCode 

order by T.EmpCode, S_EarnCompCodeColumn1 Nulls Last, S_EarnCompCodeColumn2 Nulls Last, S_DedCompCodeColumn1 Nulls Last, S_DedCompCodeColumn2 Nulls Last 


In this sql table "AVS_Payslip" has four columns, in that the values in the table are as below:


S_EarnCompCodeColumn1 S_EarnCompCodeColumn2 S_DedCompCodeColumn1 S_DedCompCodeColumn2
ADHOC CONVY PF PT
ADJADD DA RD RPLI
ATTNS_BNS DRIVE ADVANCE STORE
BASIC EXTRA_DUTY ESI  
BATH_ALW   INC_TAX  
BONUS   BKRD_ADV  
CCA      
MONT_SAL      
PRD      


On Thursday, 12 March 2015 6:53 PM, "Vishal Tiwari vishualsoft@... [firebird-support]" <firebird-support@yahoogroups.com> wrote:


 
Hi SET,

It is not table values, the table you shown is the result of my SQL i.e. my sql gives the result as your table. Sorry for last wrong explanation.


On Thursday, 12 March 2015 6:47 PM, "Vishal Tiwari vishualsoft@... [firebird-support]" <firebird-support@yahoogroups.com> wrote:


 
Table values are as you shown:

MyTable
FieldA FieldB FieldC
1 2 3
1 2 <null>
1 <null> 2
2 3 4
2 <null> <null>
<null> 2 3


On Thursday, 12 March 2015 6:32 PM, Vishal Tiwari <vishualsoft@...> wrote:


Hi SET,

I have already tried but still not getting the result. Last column displays Null value in middle of some rows.

With Best Regards.

Vishal


On Thursday, 12 March 2015 6:26 PM, "Svein Erling Tysvær svein.erling.tysvaer@... [firebird-support]" <firebird-support@yahoogroups.com> wrote:


 
>I am using Firebird database with 2.1 version. I have one issue in Order By clause.
>I have SQL which gives multile records for multiple employees, i.e. one employee has multiple records as an output in SQL.
>I have Four columns in Order By Clause and I want every columns Null value should be displayed after Not Null value in every column.
>I googled and found that if I Use
>Order By Column1 Asc Nulls Last
>It works very well for the first columns but for the remaining two columns it doesn't work i.e. for these two remaining columns the
>Null value comes in middle i.e. first some values Not Null, then Null Values and then again Not Null Values.
>I need to display Null Values at the end of every Not Null value for every Four columns specified in Order By Clause for every employee.
>I tried Case When, then Asc for every column in Order By clause, but didn't get the expected result.

This type of question is often best asked with an example. Let's say you have these data:

MyTable
FieldA FieldB FieldC
1 2 3
1 2 <null>
1 <null> 2
2 3 4
2 <null> <null>
<null> 2 3

To get the result in the order it has above, I would use

ORDER BY FieldA NULLS LAST, FieldB NULLS LAST, FieldC NULLS LAST

If you for some strange reason want THIS order (the columns with the largest number of nulls should be last):

FieldA FieldB FieldC
1 2 3
2 3 4
1 2 <null>
1 <null> 2
<null> 2 3
2 <null> <null>

then you need your CASE construct to be something like:

ORDER BY IIF(FieldA IS NULL, 2, 0)+IIF(FieldB IS NULL, 3, 0)+IIF(FieldC IS NULL, 4, 0), FieldA, FieldB, FieldC

If there are four fields to order by, you have to use minimum 3, 4, 5 and 6 rather than 2, 3 and 4.

HTH,
Set