Back to basics
-
Comments posted to this topic are about the item Back to basics
-
Great question on data types. Thanks.
-
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂
Thanks
Vinay Kumar
-----------------------------------------------------------------
Keep Learning - Keep Growing !!! -
Nice question, thanks!
Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP -
What if i define @s-2 as BIGINT
Can you give me a real time scenario as in this operator would be useful. i am just a bit curious as i have never used used it.
-
Danny Ocean (7/1/2013)
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂It provides a neat way of sending multiple options as a single integer parameter.
For example, let's say you have a table called "Locations" with 2 columns, LocationID and Location, containing the following values:
LocationID Location
1 London
2 Dublin
4 Paris
8 Berlin
16 New York
etc...
Then you could select any combination of Location values as follows:
declare @Selection int;
set @Selection=10; -- (this will select Dublin and Paris, because Dublin's LocationID plus Paris's LocationID equals 10)
select
Location
from
Locations
where
LocationId & @Selection>0;
-
martin.whitton (7/2/2013)
Danny Ocean (7/1/2013)
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂It provides a neat way of sending multiple options as a single integer parameter.
For example, let's say you have a table called "Locations" with 2 columns, LocationID and Location, containing the following values:
LocationID Location
1 London
2 Dublin
4 Paris
8 Berlin
16 New York
etc...
Then you could select any combination of Location values as follows:
declare @Selection int;
set @Selection=10; -- (this will select Dublin and Paris, because Dublin's LocationID plus Paris's LocationID equals 10)
select
Location
from
Locations
where
LocationId & @Selection>0;
Thanks martin 🙂
Thanks
Vinay Kumar
-----------------------------------------------------------------
Keep Learning - Keep Growing !!! -
martin.whitton (7/2/2013)
It provides a neat way of sending multiple options as a single integer parameter.Nice example Martin 🙂
~ Lokesh Vij
Guidelines for quicker answers on T-SQL question[/url]
Guidelines for answers on Performance questionsLink to my Blog Post --> www.SQLPathy.com[/url]
Follow me @Twitter
-
Danny Ocean (7/1/2013)
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂Hi, another example where BIT comparison is useful, msdb..sysschedules keeps the freq_interval in bitwise value 🙂
use [msdb]
go
create table #DaysOfWeekBitWise(
[bitValue] [tinyint] NOT NULL PRIMARY KEY,
[name] [varchar](10) NULL,
)
go
insert into #DaysOfWeekBitWise ([bitValue], [name])
values (1, N'Sunday')
, (2, N'Monday')
, (4, N'Tuesday')
, (8, N'Wednesday')
, (16, N'Thursday')
, (32, N'Friday')
, (64, N'Saturday')
go
select j.name
, case when j.enabled = 1 then 'Yes' else 'No' end as enabled
, jsch.next_run_date
, jsch.next_run_time
--, jst.*
, s.freq_interval
, ISNULL( STUFF( (SELECT N', ' + name FROM #DaysOfWeekBitWise AS B WHERE B.bitValue & s.freq_interval = B.bitValue FOR XML PATH('') ), 1, 2, '' ), 'None' ) AS backup_schedule
from msdb.dbo.sysjobs as j
left join msdb.dbo.sysjobschedules as jsch
on jsch.job_id = j.job_id
left join msdb.dbo.sysschedules as s
on s.schedule_id = jsch.schedule_id
order by j.name
go
drop table #DaysOfWeekBitWise
go
Cheers
-
Patibandla (7/2/2013)
What if i define @s-2 as BIGINTCan you give me a real time scenario as in this operator would be useful. i am just a bit curious as i have never used used it.
The last time I saw it used in a database was similar to the city option example given. In this instance, it was used to determine permissions across multiple databases by comparing the database 'lock' (say '01001001') to the user 'key' (say '11011001'). If the bitwise AND came back the same as the database lock, then you had access to the database.
I would note the field is semantically overloaded. But, that is a different discussion.
[font="Verdana"]Please don't go. The drones need you. They look up to you.[/font]
Connect to me on LinkedIn -
raulggonzalez (7/2/2013)
Danny Ocean (7/1/2013)
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂Hi, another example where BIT comparison is useful, msdb..sysschedules keeps the freq_interval in bitwise value 🙂
use [msdb]
go
create table #DaysOfWeekBitWise(
[bitValue] [tinyint] NOT NULL PRIMARY KEY,
[name] [varchar](10) NULL,
)
go
insert into #DaysOfWeekBitWise ([bitValue], [name])
values (1, N'Sunday')
, (2, N'Monday')
, (4, N'Tuesday')
, (8, N'Wednesday')
, (16, N'Thursday')
, (32, N'Friday')
, (64, N'Saturday')
go
select j.name
, case when j.enabled = 1 then 'Yes' else 'No' end as enabled
, jsch.next_run_date
, jsch.next_run_time
--, jst.*
, s.freq_interval
, ISNULL( STUFF( (SELECT N', ' + name FROM #DaysOfWeekBitWise AS B WHERE B.bitValue & s.freq_interval = B.bitValue FOR XML PATH('') ), 1, 2, '' ), 'None' ) AS backup_schedule
from msdb.dbo.sysjobs as j
left join msdb.dbo.sysjobschedules as jsch
on jsch.job_id = j.job_id
left join msdb.dbo.sysschedules as s
on s.schedule_id = jsch.schedule_id
order by j.name
go
drop table #DaysOfWeekBitWise
go
Cheers
Thanks raulggonzalez 🙂
Thanks
Vinay Kumar
-----------------------------------------------------------------
Keep Learning - Keep Growing !!! -
Good question, genuinely back to basics, but as your int value was 32767 wouldn't 32512 have been a better distractor than 65280?
Tom
-
Patibandla (7/2/2013)
What if i define @s-2 as BIGINTAccording to BOL, [Bitwise Operations (Transact-SQL) bitwise operations don't support bigint; in practise (in SQL 2012 anyway) you can mix and match bit, tinyint, smallint, int, and bigint freely with bitwise AND, bitwise OR, and bitwise XOR. I suspect that this is an error in BOL and bigint actually is supported, but it would be risky to use bigint with bitwise operators for production without confirmation from Microsoft that this is the case. There's a community comment on the page that saying that bigint works, but MS don't appear to police those at all.
Tom
-
Thanks for the question!
Everything is awesome! -
martin.whitton (7/2/2013)
Danny Ocean (7/1/2013)
Good question. But i never feel to use "Bitwise AND" (&) in real working scenario. It will good, if anyone come with some real working example. 🙂It provides a neat way of sending multiple options as a single integer parameter.
For example, let's say you have a table called "Locations" with 2 columns, LocationID and Location, containing the following values:
LocationID Location
1 London
2 Dublin
4 Paris
8 Berlin
16 New York
etc...
Then you could select any combination of Location values as follows:
declare @Selection int;
set @Selection=10; -- (this will select Dublin and Paris, because Dublin's LocationID plus Paris's LocationID equals 10)
select
Location
from
Locations
where
LocationId & @Selection>0;
I'm confused. Doesn't 2 (Dublin) and 8 (Berlin) equal 10 not 2 (Dublin) and 4 (Paris)? What am I missing?
Viewing 15 posts - 1 through 15 (of 28 total)
You must be logged in to reply to this topic. Login to reply