Re: Concatenated Indexes V6.0.27+

About my query on Concatenated Indexes

   (AIRLINE + TCKT_NO)  I think some people have misunderstood the question.

 I WILL be running a query using both fields.  Yet , I want to know whether ordering the fields in the Index  makes a difference.

 I understand that it does not make a difference how I order the  fields in the Query itself, the optimiser will identify that there  exists an Index on both fields and will use it.

 But, somewhere, the DBA Guide says that a concatenated index  should be created such that the more selective field is first  in the key-list.
 That is why I wish to know whether AIRLINE+TCKT_NO is  better or TCKT_NO+AIRLINE is better,
 assuming that TCKT_NO is more selective.

 The supplementary questions are :

1. What if TCKT_NO is a number field ?
2. What if the combination is UNIQUE ?