Database

declare cur cursor for Select Table_Name From INFORMATION_SCHEMA.COLUMNS Where column_name = 'INV_DATE'
declare @tablename nvarchar(max)
declare @sqlstring nvarchar(max)
open cur
fetch next from cur into @tablename
while @@fetch_status=0
begin
--print @tablename

set @sqlstring = 'update '+@tablename+' SET INV_DATE = CONVERT(varchar(10),INV_DATE,105)'

exec sp_executesql @sqlstring

fetch next from cur into @tablename
end

close cur
deallocate cur

Please suggest me a solution 

current format:2016-03-31 00:00:00.000
Required Format:31-03-2016
DataType:DateTime

I tried to copy data and changing to DateTime using temp field.But also getting the same error.

<pre lang="SQL">alter table GL add GL_DATE1 datetime null
update GL set GL_DATE=convert(datetime,GL_DATE,104)-------->Getting error here
update GL set GL_DATE1=GL_DATE
alter table GL drop column GL_DATE
SP_RENAME 'GL.GL_DATE1','GL_DATE','column'

1. create object "SqlConnection" and let connection opened during service (webservice) works
2. using the instruction below every time I want to do a modification in dtatabase

 using (SqlConnection sqlconnection = GetSqlConnection(connectionString, false))
                {
                    sqlconnection.Open();
.....

}

public static SqlConnection GetSqlConnection(string connectionString, bool disablePooling = true, bool forceMasterDB = false)
       {
           if (disablePooling || forceMasterDB)
           {
               SqlConnectionStringBuilder sqlConnBuilder = new SqlConnectionStringBuilder(connectionString);

               if (disablePooling)
                   sqlConnBuilder.Pooling = false;

               if (forceMasterDB)
                   sqlConnBuilder.InitialCatalog = "master";

               connectionString = sqlConnBuilder.ConnectionString;
           }
           return new SqlConnection(connectionString);
       }

1. Get the first 3 characters from a string, no matter alphabets or numerical values but not special characters, like for example if I have file name A00Temp then it should give me A00 and if the string is _A00Temp then still it should give me the A00 only but not _A0, if it has ABCTemp then it should give me ABC
2. the 2nd need is if I have a string with alphabets, numerical and special characters then it should give me only alphabets from that string
   for exmple if I have: Abc def 230 then I should get abcdef, if I the string is _abc$#def then I should get only abcdef.

SELECT * 
    FROM NexGen.dbo.AttemptedRuns
    WHERE BaySerialNumber = '1545300531'

SELECT  ar.Id as AttemptedRunId,
        ar.AccessionId,
        ar.StartTime,
        ar.BaySerialNumber,
        ar.CartridgeId,
        ar.Result as AttemptedRunResult,
        b.Location as BayLocation
    FROM NexGen.dbo.AttemptedRuns ar
    LEFT JOIN NexGen.dbo.Bays b on b.SerialNumber = ar.BaySerialNumber
    WHERE ar.BaySerialNumber = '1545300531'