sql nerchukundam randiii... Ms sql server technology discussions...

[loveindia]

Just now, k2s said:

antey endo seppochu kada man 

imp un-imp antey saripothunda 

endi daddy pillalni ala rape chestunnav.. is this good for a aged person like u man...

[loveindia]

1 minute ago, mtkr said:

avi ekkado copy kotti raasukunnaviii...

guruvu 

               

vinadaaniki idi chaala baagundi man.. keep it coming man... 

[k2s]

Just now, loveindia said:

endi daddy pillalni ala rape chestunnav.. is this good for a aged person like u man...

Anxiety to know more man 

[loveindia]

1 minute ago, k2s said:

Anxiety to know more man 

ee age lo aa anxiety avasaramaa man... 

[bussuboy]

GP. Keep it up and updated

 

[k2s]

8 minutes ago, loveindia said:

ee age lo aa anxiety avasaramaa man... 

chaduvu ki 

prema / love / ishq  ki vayasu tho emi sambandam man ?

[k2s]

34 minutes ago, k2s said:

qochens sir 

1) what is difference between Table/Index Scan vs Seek ? How SQL server evaluate(search row) in each case ? 

2) Create Index on filtered, aggregated col,  antey ela chestharu ? oka table lo index ni ela create chestharu ?

3) Join ki correlated sub query ki difference enti ? how does SQL server evaluate in each case ? why join is preferred ?

@loveindia @mtkr help ??

[sri_india]

10 minutes ago, loveindia said:

ee age lo aa anxiety avasaramaa man... 

batch eppudu start chesthunaru guruji

[loveindia]

8 minutes ago, sri_india said:

batch eppudu start chesthunaru guruji

r u sishya or sishyuraalu man.. 

[k2s]

8 minutes ago, loveindia said:

r u sishya or sishyuraalu man.. 

y so gender biased man ? naaaledgy is wine noo.. pour it on everyone 

[sri_india]

18 minutes ago, loveindia said:

r u sishya or sishyuraalu man.. 

ippudu shisya antee no batch antavaaa  ... shishya neee

[mtkr]

23 minutes ago, k2s said:

qochens sir 

1) what is difference between Table/Index Scan vs Seek ? How SQL server evaluate(search row) in each case ? 

2) Create Index on filtered, aggregated col,  antey ela chestharu ? oka table lo index ni ela create chestharu ?

3) Join ki correlated sub query ki difference enti ? how does SQL server evaluate in each case ? why join is preferred ?

1) Index scan is looking all data pages from first to last... index seek is looking specific data pages...

scan preferred whn tbl is small..

seek preferred whn tbl is large...

orders table having no index on it
select * from orders --- table scan

orders table having clustered index on it
select * from orders --- index scan

orders table having clustered index on it
select * from orders where id = 2 --- index seek

https://blogs.msdn.microsoft.com/craigfr/2006/06/26/scans-vs-seeks/

 

2) create index index_name on table_name (column_name)

 

3) correlated sub query -  its a subquery wch uses values from outer query for execution 

(frm ggle)

A correlated subquery is one which uses values from the parent query. This kind of query tends to run row-by-row, once for each row returned by the outer query, and thus decreases SQL query performance. New developers are often caught structuring their queries in this way—because it’s usually the easy route.

Here’s an example of a correlated subquery:

SELECT c.Name, 
       c.City,
       (SELECT CompanyName FROM Company WHERE ID = c.CompanyID) AS CompanyName 
FROM Customer c
In particular, the problem is that the inner query (SELECT CompanyName…) is run for each row returned by the outer query (SELECT c.Name…). But why go over the Company again and again for every row processed by the outer query?

A more efficient performance tuning technique would be to refactor the correlated subquery as a join:

SELECT c.Name, 
       c.City, 
       co.CompanyName 
FROM Customer c 
    LEFT JOIN Company co
        ON c.CompanyID = co.CompanyID
In this case, we go over the Company table just once, at the start, and JOIN it with the Customer table. From then on, we can select the values we need (co.CompanyName) more efficiently.

[sri_india]

indhulo disco chusthuntee urgent gaa SQL technologies ki shift ayipovali ani undi... chala support undi ee DB lo SQL tech ki 

[sanbk]

Why can't you build non clustered indexes on all the columns provided you have good CPU performance (wipro interveiw question)

SSIS vi post chestha next... 

[ronitreddy]

54 minutes ago, k2s said:

antey endo seppochu kada man 

imp un-imp antey saripothunda 

daddy..pillola mida ala satires veyocha?