sql server 2008 - What does the third parameter in CONVERT() do? -

query

get joining year,joining month , joining date employee table

this query have perform. write following script:

select      substring (convert(varchar,joining_date,103),7,4) ,      substring (convert(varchar,joining_date,100),1,3) ,      substring (convert(varchar,joining_date,100),5,2)       employee 

the result is: http://d.pr/i/vobi

but when changed convert(varchar,joining_date,100) convert(varchar,joining_date,101)

result this: http://d.pr/i/g5fz

can please explain parameter means?

there several different ways can format date using convert(varchar.... these documented on msdn site or different sites online.

using convert(varchar..., date, 100) places date in format:

mon dd yyyy hh:mmam (or pm) may 10 2013 12:55pm 

using convert(varchar...date, 101) puts date in format:

mm/dd/yyyy 05/10/2013 

see demo

my suggestion whenever implement these conversions, sure give length on varchar(10), etc.

based on looks returning, can eliminate of convert/substring statements using , implement other functions same result:

select year(joining_date) [year] ,    convert(varchar(3),joining_date,100) [month] ,    day(joining_date) [day] employee