sql-server-2008-r2

问题 I have an SQL table in which I store large string values that must be unique. In order to ensure the uniqueness, I have a unique index on a column in which I store a string representation of the MD5 hash of the large string. The C# app that saves these records uses the following method to do the hashing: public static string CreateMd5HashString(byte[] input) { var hashBytes = MD5.Create().ComputeHash(input); return string.Join("", hashBytes.Select(b => b.ToString("X"))); } In order to call

问题 Recently I found a couple of tables in a Database with no Clustered Indexes defined. But there are non-clustered indexes defined, so they are on HEAP. On analysis I found that select statements were using filter on the columns defined in non-clustered indexes. Not having a clustered index on these tables affect performance? 回答1: It's hard to state this more succinctly than SQL Server MVP Brad McGehee: As a rule of thumb, every table should have a clustered index. Generally, but not always,

问题 Assuming that I have the following T-SQL code: SELECT * FROM Foo f INNER JOIN Bar b ON b.BarId = f.BarId; WHERE b.IsApproved = 1; The following one also returns the same set of rows: SELECT * FROM Foo f INNER JOIN Bar b ON (b.IsApproved = 1) AND (b.BarId = f.BarId); This might not be the best case sample here but is there any performance difference between these two? 回答1: No, the query optimizer is smart enough to choose the same execution plan for both examples. You can use SHOWPLAN to check

问题 I am trying to calculate the distance between two positions on a map. I have stored in my data: Longitude, Latitude, X POS, Y POS. I have been previously using the below snippet. DECLARE @orig_lat DECIMAL DECLARE @orig_lng DECIMAL SET @orig_lat=53.381538 set @orig_lng=-1.463526 SELECT *, 3956 * 2 * ASIN( SQRT( POWER(SIN((@orig_lat - abs(dest.Latitude)) * pi()/180 / 2), 2) + COS(@orig_lng * pi()/180 ) * COS(abs(dest.Latitude) * pi()/180) * POWER(SIN((@orig_lng - dest.Longitude) * pi()/180 / 2)

问题 I am trying to calculate the distance between two positions on a map. I have stored in my data: Longitude, Latitude, X POS, Y POS. I have been previously using the below snippet. DECLARE @orig_lat DECIMAL DECLARE @orig_lng DECIMAL SET @orig_lat=53.381538 set @orig_lng=-1.463526 SELECT *, 3956 * 2 * ASIN( SQRT( POWER(SIN((@orig_lat - abs(dest.Latitude)) * pi()/180 / 2), 2) + COS(@orig_lng * pi()/180 ) * COS(abs(dest.Latitude) * pi()/180) * POWER(SIN((@orig_lng - dest.Longitude) * pi()/180 / 2)

问题 I've got dirty data in a column with variable alpha length. I just want to strip out anything that is not 0-9. I do not want to run a function or proc. I have a script that is similar that just grabs the numeric value after text, it looks like this: Update TableName set ColumntoUpdate=cast(replace(Columnofdirtydata,'Alpha #','') as int) where Columnofdirtydata like 'Alpha #%' And ColumntoUpdate is Null I thought it would work pretty good until I found that some of the data fields I thought

问题 I've been stuck for the past two days execute it give the error: The data types varchar and int are incompatible in the concat operator Here is my table: create table salestable ( id int identity(1,1) not null primary key, empid char(5), datesold date, monthonly varchar(50), amount money ) This code inserts the dummy record into dbo.salestable for working in salestable, debug and step into the code that give the debug and understanding code declare @outercounter int = 1 declare @innercounter

问题 Say I have the following databases in SQL Server 2008 R2 db1, db2, db3, db4, db5......dbn each database has a table A which contains the columns C1,C2,C3 I can write the following Select statement on two databases to get the data across them: Select C1,C2,C3 FROM db1.dbo.A UNION ALL Select C1,C2,C3 FROM db2.dbo.A However if I have 50 databases on the same server I don't want to write a UNION ALL for each. Can someone give me a script to do this? I can modify the script to exclude system

问题 Note : This post is slightly change with previous post. I have the following table with the details as shown below in the example. Example : Table: test create table test ( cola varchar(10), colb varchar(10), colc varchar(10) ); Insertion : insert into test values('101','1234','A1'); insert into test values('101','4321','A2'); insert into test values('201','5678','A3'); insert into test values('301','8765','A4'); insert into test values('401','9877','A1'); insert into test values('101','9997'

问题 I have a table called MyTextstable (myTextsTable_id INT, myTextsTable_text VARCHAR(MAX)) . This table has around 4 million records and I am trying to remove any instance of the ASCII characters in the following range(s) the VARCHAR(MAX) column myTextsTable_text . 00 - 08 11 - 12 14 - 31 127 I have written the following SQL query, which is taking under 10 minutes on SQL Server 2012, but failed to execute on SQL Server 2008 R2 even after two hours (so I stopped the execution). Please note I