Monday, February 22, 2010

Forcing index- SQL

So if cust_num is the 6 th index created on the table. Here is how you force the index while querying the database table :

select * from tranhist (6) where cust_num='AA25150'

Thursday, February 18, 2010

Excel Printing header on each line

Goto File -> Page Setup -> goto sheet tab -> In Print Titles section, Rows to repeat at top, enter the range of rows you would like to repeat : $1:$1

http://www.mrexcel.com/tip129.shtml

Wednesday, February 3, 2010

SQL Not in vs Join example

Obviously SQL join is more efficient than the not in clause. Here is an example of both.


Most inefficient Not in query :

select count(*)
from
wire_instr w
where
w.short_code
not in (select short_code
from nostro_accts)


Slightly better Not Exists query :

select count(*) from
wire_instr w
where not exists(
select 1
from nostro_accts n where
n.short_code=w.short_code)


Finally the Join query :

Join infact creates a new table which

select w.short_code as wshort,n.short_code as nshort from wire_instr w
left outer join
nostro_accts n
on n.short_code=w.short_code
where n.short_code=null

Enjoy
-Sunny