Based on the ideas in this post, I've made an improved and dynamic version to help in determining the violating records when inserting into a table:
http://sqlblogcasts.com/blogs/danny/archive/2008/01/12/scuffling-with-string-or-binary-data-would-be-truncated.aspx
create procedure cst_checktruncatederror as
begin
set nocount on
declare @src nvarchar(max) = 'sourcetable'
declare @tgt nvarchar(max) = 'targettable'
declare @cols nvarchar(max)
declare @sql nvarchar(max)
-- create temporary empty version of destination table (target proxy)
-- note: use a global temp table, because a normal one goes out-of-scope when the dynamic sql returns
if (object_id('tempdb..##target') is not null) drop table ##target
set @sql = concat('SELECT * INTO ##target FROM ',@tgt,' where 1=0')
print @sql
exec sp_executesql @sql
-- get a comma-separated string with block-quoted columnnames that are comparable
set ansi_padding on
set @sql = concat('
select @colsOUT =
substring
(
(
select concat('',['',column_name,'']'')
from information_schema.columns
where table_name = ''',@tgt,'''
and data_type <> ''geography''
for xml path(''''), type
).value(''.'',''nvarchar(max)'')
,2,100000
)
')
print @sql
exec sp_executesql @sql, N'@colsOUT nvarchar(max) OUTPUT', @colsOUT=@cols OUTPUT
print @cols
-- load source to target proxy
set @sql = concat('
INSERT INTO ##target (',@cols,')
SELECT ',@cols,'
FROM ',@src,'
')
print @sql
SET ANSI_WARNINGS OFF -- truncates fields instead of throwing "string or binary data would be truncated error" error!
-- 1. do not use * to insert, because the column order might be off
-- 2. wrap fieldnames in blockquotes [] because reserved words might have been used, e.g. STATE or UNIQUE
-- 3. exclude data types: geography
-- 4. TO DO: destination columns might be NULLable, while the source is not. That results in a different error
exec sp_executesql @sql
SET ANSI_WARNINGS ON
-- return violating records
set @sql = concat('
SELECT ',@cols,'
FROM ',@src,'
except
SELECT ',@cols,'
FROM ##target
')
print @sql
exec sp_executesql @sql
-- clean up
if (object_id('tempdb..##target') is not null) drop table ##target
end