sql query to return differences between two tables
SqlSql ServerSql Server-2008Sql Server-2005Sql Problem Overview
I am trying to compare two tables, SQL Server, to verify some data. I want to return all the rows from both tables where data is either in one or the other. In essence, I want to show all the discrepancies. I need to check three pieces of data in doing so, FirstName, LastName and Product.
I'm fairly new to SQL and it seems like a lot of the solutions I'm finding are over complicating things. I don't have to worry about NULLs.
I started by trying something like this:
SELECT DISTINCT [First Name], [Last Name], [Product Name] FROM [Temp Test Data]
WHERE ([First Name] NOT IN (SELECT [First Name]
FROM [Real Data]))
I'm having trouble taking this further though.
Thanks!
EDIT:
Based on the answer by @treaschf I have been trying to use a variation of the following query:
SELECT td.[First Name], td.[Last Name], td.[Product Name]
FROM [Temp Test Data] td FULL OUTER JOIN [Data] AS d
ON td.[First Name] = d.[First Name] AND td.[Last Name] = d.[Last Name]
WHERE (d.[First Name] = NULL) AND (d.[Last Name] = NULL)
But I keep getting 0 results back, when I know that there is at least 1 row in td that is not in d.
EDIT:
Ok, I think I figured it out. At least in my few minutes of testing it seems to work good enough.
SELECT [First Name], [Last Name]
FROM [Temp Test Data] AS td
WHERE (NOT EXISTS
(SELECT [First Name], [Last Name]
FROM [Data] AS d
WHERE ([First Name] = td.[First Name]) OR ([Last Name] = td.[Last Name])))
This is basically going to tell me what is in my test data that is not in my real data. Which is completely fine for what I need to do.
Sql Solutions
Solution 1 - Sql
( SELECT * FROM table1
EXCEPT
SELECT * FROM table2)
UNION ALL
( SELECT * FROM table2
EXCEPT
SELECT * FROM table1)
Solution 2 - Sql
IF you have tables A and B, both with colum C, here are the records, which are present in table A but not in B:
SELECT A.*
FROM A
LEFT JOIN B ON (A.C = B.C)
WHERE B.C IS NULL
To get all the differences with a single query, a full join must be used, like this:
SELECT A.*, B.*
FROM A
FULL JOIN B ON (A.C = B.C)
WHERE A.C IS NULL OR B.C IS NULL
What you need to know in this case is, that when a record can be found in A, but not in B, than the columns which come from B will be NULL, and similarly for those, which are present in B and not in A, the columns from A will be null.
Solution 3 - Sql
I know that this may not be a popular answer but I do agree with @Randy Minder on using third party tool when more complex comparison is needed.
This specific case here is easy and for this case such tools are not needed but this can get complex easily if you introduce more columns, databases on two servers, more complex comparison criteria and such.
There are a lot of these tools such as ApexSQL Data Diff or Quest Toad and you can always use them in trial mode to get the job done.
Solution 4 - Sql
To get all the differences between two tables, you can use like me this SQL request :
SELECT 'TABLE1-ONLY' AS SRC, T1.*
FROM (
SELECT * FROM Table1
EXCEPT
SELECT * FROM Table2
) AS T1
UNION ALL
SELECT 'TABLE2-ONLY' AS SRC, T2.*
FROM (
SELECT * FROM Table2
EXCEPT
SELECT * FROM Table1
) AS T2
;
Solution 5 - Sql
Simple variation on @erikkallen answer that shows which table the row is present in:
( SELECT 'table1' as source, * FROM table1
EXCEPT
SELECT * FROM table2)
UNION ALL
( SELECT 'table2' as source, * FROM table2
EXCEPT
SELECT * FROM table1)
If you get an error
> All queries combined using a UNION, INTERSECT or EXCEPT operator must have an equal number of expressions in their target lists.
then it may help to add
( SELECT 'table1' as source, * FROM table1
EXCEPT
SELECT 'table1' as source, * FROM table2)
UNION ALL
( SELECT 'table2' as source, * FROM table2
EXCEPT
SELECT 'table2' as source, * FROM table1)
Solution 6 - Sql
If you want to get which column values are different, you could use Entity-Attribute-Value model:
declare @Data1 xml, @Data2 xml
select @Data1 =
(
select *
from (select * from Test1 except select * from Test2) as a
for xml raw('Data')
)
select @Data2 =
(
select *
from (select * from Test2 except select * from Test1) as a
for xml raw('Data')
)
;with CTE1 as (
select
T.C.value('../@ID', 'bigint') as ID,
T.C.value('local-name(.)', 'nvarchar(128)') as Name,
T.C.value('.', 'nvarchar(max)') as Value
from @Data1.nodes('Data/@*') as T(C)
), CTE2 as (
select
T.C.value('../@ID', 'bigint') as ID,
T.C.value('local-name(.)', 'nvarchar(128)') as Name,
T.C.value('.', 'nvarchar(max)') as Value
from @Data2.nodes('Data/@*') as T(C)
)
select
isnull(C1.ID, C2.ID) as ID, isnull(C1.Name, C2.Name) as Name, C1.Value as Value1, C2.Value as Value2
from CTE1 as C1
full outer join CTE2 as C2 on C2.ID = C1.ID and C2.Name = C1.Name
where
not
(
C1.Value is null and C2.Value is null or
C1.Value is not null and C2.Value is not null and C1.Value = C2.Value
)
Solution 7 - Sql
You can use except , for example something like this :
-- DB1..Tb1 have values than DB2..Tb1 not have
Select Col1,Col2,Col3 From DB1..Tb1
except
Select Col1,Col2,Col3 From DB2..Tb1
-- Now we change order
-- DB2..Tb1 have values than DB1..Tb1 not have
Select Col1,Col2,Col3 From DB2..Tb1
except
Select Col1,Col2,Col3 From DB1..Tb1
Solution 8 - Sql
Presenting the Cadillac of Diffs as an SP. See within for the basic template that was based on answer by @erikkallen. It supports
- Duplicate row sensing (most other answers here do not)
- Sort results by argument
- Limit to specific columns
- Ignore columns (e.g. ModifiedUtc)
- Cross database tables names
- Temp tables (use as workaround to diff views)
Usage:
exec Common.usp_DiffTableRows '#t1', '#t2';
exec Common.usp_DiffTableRows
@pTable0 = 'ydb.ysh.table1',
@pTable1 = 'xdb.xsh.table2',
@pOrderByCsvOpt = null, -- Order the results
@pOnlyCsvOpt = null, -- Only compare these columns
@pIgnoreCsvOpt = null; -- Ignore these columns (ignored if @pOnlyCsvOpt is specified)
Code:
alter proc [Common].[usp_DiffTableRows]
@pTable0 varchar(300),
@pTable1 varchar(300),
@pOrderByCsvOpt nvarchar(1000) = null, -- Order the Results
@pOnlyCsvOpt nvarchar(4000) = null, -- Only compare these columns
@pIgnoreCsvOpt nvarchar(4000) = null, -- Ignore these columns (ignored if @pOnlyCsvOpt is specified)
@pDebug bit = 0
as
/*---------------------------------------------------------------------------------------------------------------------
Purpose: Compare rows between two tables.
Usage: exec Common.usp_DiffTableRows '#a', '#b';
Modified By Description
---------- ---------- -------------------------------------------------------------------------------------------
2015.10.06 crokusek Initial Version
2019.03.13 crokusek Added @pOrderByCsvOpt
2019.06.26 crokusek Support for @pIgnoreCsvOpt, @pOnlyCsvOpt.
2019.09.04 crokusek Minor debugging improvement
2020.03.12 crokusek Detect duplicate rows in either source table
---------------------------------------------------------------------------------------------------------------------*/
begin try
if (substring(@pTable0, 1, 1) = '#')
set @pTable0 = 'tempdb..' + @pTable0; -- object_id test below needs full names for temp tables
if (substring(@pTable1, 1, 1) = '#')
set @pTable1 = 'tempdb..' + @pTable1; -- object_id test below needs full names for temp tables
if (object_id(@pTable0) is null)
raiserror('Table name is not recognized: ''%s''', 16, 1, @pTable0);
if (object_id(@pTable1) is null)
raiserror('Table name is not recognized: ''%s''', 16, 1, @pTable1);
create table #ColumnGathering
(
Name nvarchar(300) not null,
Sequence int not null,
TableArg tinyint not null
);
declare
@usp varchar(100) = object_name(@@procid),
@sql nvarchar(4000),
@sqlTemplate nvarchar(4000) =
'
use $database$;
insert into #ColumnGathering
select Name, column_id as Sequence, $TableArg$ as TableArg
from sys.columns c
where object_id = object_id(''$table$'', ''U'')
';
set @sql = replace(replace(replace(@sqlTemplate,
'$TableArg$', 0),
'$database$', (select DatabaseName from Common.ufn_SplitDbIdentifier(@pTable0))),
'$table$', @pTable0);
if (@pDebug = 1)
print 'Sql #CG 0: ' + @sql;
exec sp_executesql @sql;
set @sql = replace(replace(replace(@sqlTemplate,
'$TableArg$', 1),
'$database$', (select DatabaseName from Common.ufn_SplitDbIdentifier(@pTable1))),
'$table$', @pTable1);
if (@pDebug = 1)
print 'Sql #CG 1: ' + @sql;
exec sp_executesql @sql;
if (@pDebug = 1)
select * from #ColumnGathering;
select Name,
min(Sequence) as Sequence,
convert(bit, iif(min(TableArg) = 0, 1, 0)) as InTable0,
convert(bit, iif(max(TableArg) = 1, 1, 0)) as InTable1
into #Columns
from #ColumnGathering
group by Name
having ( @pOnlyCsvOpt is not null
and Name in (select Value from Common.ufn_UsvToNVarcharKeyTable(@pOnlyCsvOpt, default)))
or
( @pOnlyCsvOpt is null
and @pIgnoreCsvOpt is not null
and Name not in (select Value from Common.ufn_UsvToNVarcharKeyTable(@pIgnoreCsvOpt, default)))
or
( @pOnlyCsvOpt is null
and @pIgnoreCsvOpt is null)
if (exists (select 1 from #Columns where InTable0 = 0 or InTable1 = 0))
begin
select 1; -- without this the debugging info doesn't stream sometimes
select * from #Columns order by Sequence;
waitfor delay '00:00:02'; -- give results chance to stream before raising exception
raiserror('Columns are not equal between tables, consider using args @pIgnoreCsvOpt, @pOnlyCsvOpt. See Result Sets for details.', 16, 1);
end
if (@pDebug = 1)
select * from #Columns order by Sequence;
declare
@columns nvarchar(4000) = --iif(@pOnlyCsvOpt is null and @pIgnoreCsvOpt is null,
-- '*',
(
select substring((select ',' + ac.name
from #Columns ac
order by Sequence
for xml path('')),2,200000) as csv
);
if (@pDebug = 1)
begin
print 'Columns: ' + @columns;
waitfor delay '00:00:02'; -- give results chance to stream before possibly raising exception
end
-- Based on https://stackoverflow.com/a/2077929/538763
-- - Added sensing for duplicate rows
-- - Added reporting of source table location
--
set @sqlTemplate = '
with
a as (select ~, Row_Number() over (partition by ~ order by (select null)) -1 as Duplicates from $a$),
b as (select ~, Row_Number() over (partition by ~ order by (select null)) -1 as Duplicates from $b$)
select 0 as SourceTable, ~
from
(
select * from a
except
select * from b
) anb
union all
select 1 as SourceTable, ~
from
(
select * from b
except
select * from a
) bna
order by $orderBy$
';
set @sql = replace(replace(replace(replace(@sqlTemplate,
'$a$', @pTable0),
'$b$', @pTable1),
'~', @columns),
'$orderBy$', coalesce(@pOrderByCsvOpt, @columns + ', SourceTable')
);
if (@pDebug = 1)
print 'Sql: ' + @sql;
exec sp_executesql @sql;
end try
begin catch
declare
@CatchingUsp varchar(100) = object_name(@@procid);
if (xact_state() = -1)
rollback;
-- Disabled for S.O. post
--exec Common.usp_Log
--@pMethod = @CatchingUsp;
--exec Common.usp_RethrowError
--@pCatchingMethod = @CatchingUsp;
throw;
end catch
go
create function Common.Trim
(
@pOriginalString nvarchar(max),
@pCharsToTrim nvarchar(50) = null -- specify null or 'default' for whitespae
)
returns table
with schemabinding
as
/*--------------------------------------------------------------------------------------------------
Purpose: Trim the specified characters from a string.
Modified By Description
---------- -------------- --------------------------------------------------------------------
2012.09.25 S.Rutszy/crok Modified from https://dba.stackexchange.com/a/133044/9415
--------------------------------------------------------------------------------------------------*/
return
with cte AS
(
select patindex(N'%[^' + EffCharsToTrim + N']%', @pOriginalString) AS [FirstChar],
patindex(N'%[^' + EffCharsToTrim + N']%', reverse(@pOriginalString)) AS [LastChar],
len(@pOriginalString + N'~') - 1 AS [ActualLength]
from
(
select EffCharsToTrim = coalesce(@pCharsToTrim, nchar(0x09) + nchar(0x20) + nchar(0x0d) + nchar(0x0a))
) c
)
select substring(@pOriginalString, [FirstChar],
((cte.[ActualLength] - [LastChar]) - [FirstChar] + 2)
) AS [TrimmedString]
--
--cte.[ActualLength],
--[FirstChar],
--((cte.[ActualLength] - [LastChar]) + 1) AS [LastChar]
from cte;
go
create function [Common].[ufn_UsvToNVarcharKeyTable] (
@pCsvList nvarchar(MAX),
@pSeparator nvarchar(1) = ',' -- can pass keyword 'default' when calling using ()'s
)
--
-- SQL Server 2012 distinguishes nvarchar keys up to maximum of 450 in length (900 bytes)
--
returns @tbl table (Value nvarchar(450) not null primary key(Value)) as
/*-------------------------------------------------------------------------------------------------
Purpose: Converts a comma separated list of strings into a sql NVarchar table. From
http://www.programmingado.net/a-398/SQL-Server-parsing-CSV-into-table.aspx
This may be called from RunSelectQuery:
GRANT SELECT ON Common.ufn_UsvToNVarcharTable TO MachCloudDynamicSql;
Modified By Description
---------- -------------- -------------------------------------------------------------------
2011.07.13 internet Initial version
2011.11.22 crokusek Support nvarchar strings and a custom separator.
2017.12.06 crokusek Trim leading and trailing whitespace from each element.
2019.01.26 crokusek Remove newlines
-------------------------------------------------------------------------------------------------*/
begin
declare
@pos int,
@textpos int,
@chunklen smallint,
@str nvarchar(4000),
@tmpstr nvarchar(4000),
@leftover nvarchar(4000),
@csvList nvarchar(max) = iif(@pSeparator not in (char(13), char(10), char(13) + char(10)),
replace(replace(@pCsvList, char(13), ''), char(10), ''),
@pCsvList); -- remove newlines
set @textpos = 1
set @leftover = ''
while @textpos <= len(@csvList)
begin
set @chunklen = 4000 - len(@leftover)
set @tmpstr = ltrim(@leftover + substring(@csvList, @textpos, @chunklen))
set @textpos = @textpos + @chunklen
set @pos = charindex(@pSeparator, @tmpstr)
while @pos > 0
begin
set @str = substring(@tmpstr, 1, @pos - 1)
set @str = (select TrimmedString from Common.Trim(@str, default));
insert @tbl (value) values(@str);
set @tmpstr = ltrim(substring(@tmpstr, @pos + 1, len(@tmpstr)))
set @pos = charindex(@pSeparator, @tmpstr)
end
set @leftover = @tmpstr
end
-- Handle @leftover
set @str = (select TrimmedString from Common.Trim(@leftover, default));
if @str <> ''
insert @tbl (value) values(@str);
return
end
GO
create function Common.ufn_SplitDbIdentifier(@pIdentifier nvarchar(300))
returns @table table
(
InstanceName nvarchar(300) not null,
DatabaseName nvarchar(300) not null,
SchemaName nvarchar(300),
BaseName nvarchar(300) not null,
FullTempDbBaseName nvarchar(300), -- non-null for tempdb (e.g. #Abc____...)
InstanceWasSpecified bit not null,
DatabaseWasSpecified bit not null,
SchemaWasSpecified bit not null,
IsCurrentInstance bit not null,
IsCurrentDatabase bit not null,
IsTempDb bit not null,
OrgIdentifier nvarchar(300) not null
) as
/*-----------------------------------------------------------------------------------------------------------
Purpose: Split a Sql Server Identifier into its parts, providing appropriate default values and
handling temp table (tempdb) references.
Example: select * from Common.ufn_SplitDbIdentifier('t')
union all
select * from Common.ufn_SplitDbIdentifier('s.t')
union all
select * from Common.ufn_SplitDbIdentifier('d.s.t')
union all
select * from Common.ufn_SplitDbIdentifier('i.d.s.t')
union all
select * from Common.ufn_SplitDbIdentifier('#d')
union all
select * from Common.ufn_SplitDbIdentifier('tempdb..#d');
-- Empty
select * from Common.ufn_SplitDbIdentifier('illegal name');
Modified By Description
---------- -------------- -----------------------------------------------------------------------------
2013.09.27 crokusek Initial version.
-----------------------------------------------------------------------------------------------------------*/
begin
declare
@name nvarchar(300) = ltrim(rtrim(@pIdentifier));
-- Return an empty table as a "throw"
--
--Removed for SO post
--if (Common.ufn_IsSpacelessLiteralIdentifier(@name) = 0)
-- return;
-- Find dots starting from the right by reversing first.
declare
@revName nvarchar(300) = reverse(@name);
declare
@firstDot int = charindex('.', @revName);
declare
@secondDot int = iif(@firstDot = 0, 0, charindex('.', @revName, @firstDot + 1));
declare
@thirdDot int = iif(@secondDot = 0, 0, charindex('.', @revName, @secondDot + 1));
declare
@fourthDot int = iif(@thirdDot = 0, 0, charindex('.', @revName, @thirdDot + 1));
--select @firstDot, @secondDot, @thirdDot, @fourthDot, len(@name);
-- Undo the reverse() (first dot is first from the right).
--
set @firstDot = iif(@firstDot = 0, 0, len(@name) - @firstDot + 1);
set @secondDot = iif(@secondDot = 0, 0, len(@name) - @secondDot + 1);
set @thirdDot = iif(@thirdDot = 0, 0, len(@name) - @thirdDot + 1);
set @fourthDot = iif(@fourthDot = 0, 0, len(@name) - @fourthDot + 1);
--select @firstDot, @secondDot, @thirdDot, @fourthDot, len(@name);
declare
@baseName nvarchar(300) = substring(@name, @firstDot + 1, len(@name) - @firstdot);
declare
@schemaName nvarchar(300) = iif(@firstDot - @secondDot - 1 <= 0,
null,
substring(@name, @secondDot + 1, @firstDot - @secondDot - 1));
declare
@dbName nvarchar(300) = iif(@secondDot - @thirdDot - 1 <= 0,
null,
substring(@name, @thirdDot + 1, @secondDot - @thirdDot - 1));
declare
@instName nvarchar(300) = iif(@thirdDot - @fourthDot - 1 <= 0,
null,
substring(@name, @fourthDot + 1, @thirdDot - @fourthDot - 1));
with input as (
select
coalesce(@instName, '[' + @@servername + ']') as InstanceName,
coalesce(@dbName, iif(left(@baseName, 1) = '#', 'tempdb', db_name())) as DatabaseName,
coalesce(@schemaName, iif(left(@baseName, 1) = '#', 'dbo', schema_name())) as SchemaName,
@baseName as BaseName,
iif(left(@baseName, 1) = '#',
(
select [name] from tempdb.sys.objects
where object_id = object_id('tempdb..' + @baseName)
),
null) as FullTempDbBaseName,
iif(@instName is null, 0, 1) InstanceWasSpecified,
iif(@dbName is null, 0, 1) DatabaseWasSpecified,
iif(@schemaName is null, 0, 1) SchemaWasSpecified
)
insert into @table
select i.InstanceName, i.DatabaseName, i.SchemaName, i.BaseName, i.FullTempDbBaseName,
i.InstanceWasSpecified, i.DatabaseWasSpecified, i.SchemaWasSpecified,
iif(i.InstanceName = '[' + @@servername + ']', 1, 0) as IsCurrentInstance,
iif(i.DatabaseName = db_name(), 1, 0) as IsCurrentDatabase,
iif(left(@baseName, 1) = '#', 1, 0) as IsTempDb,
@name as OrgIdentifier
from input i;
return;
end
GO
Solution 9 - Sql
Try this :
SELECT
[First Name], [Last Name]
FROM
[Temp Test Data] AS td EXCEPTION JOIN [Data] AS d ON
(d.[First Name] = td.[First Name] OR d.[Last Name] = td.[Last Name])
Much simpler to read.
Solution 10 - Sql
This will do the trick, similar with [Tiago] 1's solution, return "source" table as well.
select [First name], [Last name], max(_tabloc) as _tabloc
from (
select [First Name], [Last name], 't1' as _tabloc from table1
union all
select [First name], [Last name], 't2' as _tabloc from table2
) v
group by [Fist Name], [Last name]
having count(1)=1
result will contain differences between tables, in column _tabloc you will have table reference.
Solution 11 - Sql
For a simple smoke test where you you're trying to ensure two tables match w/out worrying about column names:
--ensure tables have matching records
Select count (*) from tbl_A
Select count (*) from tbl_B
--create temp table of all records in both tables
Select * into #demo from tbl_A
Union All
Select * from tbl_B
--Distinct #demo records = Total #demo records/2 = Total tbl_A records = total tbl_B records
Select distinct * from #demo
You can easily write a store procedure to compare a batch of tables.
Solution 12 - Sql
There is a performance issue related with the left join as well as full join with large data.
In my opinion this is the best solution:
select [First Name], count(1) e from
(select * from [Temp Test Data]
union all
select * from [Temp Test Data 2]) a
group by [First Name] having e = 1