Merge multiple tables into one table SQL Server

Merge multiple tables into one table SQL Server - sql

I want to merge 3 tables into one only to get full data with conditions below
merge 3 tables [test1], [test2], [test3] into one table [test]
If when merging, if a column is blank select from another table
Col1 exists in all 3 tables
Here is my example code to merge from table 2 into test.
MERGE INTO [dbo].[test] a
USING [dbo].[test2] b ON a.col1 = b.col1
WHEN MATCHED THEN
UPDATE
SET col1 = b.col1,
col2 = b.col2,
col3 = b.col3,
col4 = b.col4
WHERE col1 = '' OR col2 = '' OR col3 = '' OR col4 = '';
It get errors:
Incorrect syntax near the keyword 'where'.

Please try the COALESCE function rather than using the where condition. The COALESCE function takes the next value in case there is a NULL is encountered.
Merge into [dbo].[test] a
using [dbo].[test2] b
on a.col1 = b.col1
when matched then
update
set col2 = COALESCE(a.col2, b.col2),
col3 = COALESCE(a.col3, b.col3),
col4 = COALESCE(a.col4, b.col4);
So in the modified code, if the Table [dbo].[test] col2 is Null then it takes the value from [dbo].[test2]. Since you will be using COALESCE, you will be able to merge any number of values.

Can you show the table Structure.
you can use
UNION ALL Operator follow this link.
https://www.techonthenet.com/sql_server/union.php
OR mixture of INNER JOIN with UPDATE statement combining the condition on WHERE clause

Related

Aster UPDATE Column Does Not Exist

I am attempting to UPDATE the values of a column in one table based on the count of values in a source table. I am using Teradata Aster.
When I submit the following correlated subquery, I get an error stating the column does not exist despite verifying that it does exist.
UPDATE table2
SET column =
(
SELECT count(*)
FROM table1
WHERE table2.column = table1.column
)
I feel there is something idiosyncratic about Aster, but I'm not certain.

You could use below query for simple column update from another table.
UPDATE table1
SET col2 = table2.col2
FROM table2
WHERE table1.col1 = table2.col1;
and for aggregate function in update query you could use below query.
UPDATE table1
SET col2 = table2.col2
FROM (select col1, count(col2) col2 from table2 group by col1 ) table2
WHERE table1.col1 = table2.col1;
Both the queries works fine for me.

How to update table without using update keyword

I have table a ,table b with same columns .I want to replace the value in table b with table a value without using update keyword.

The question could use a bit more detail on the table structure, what exactly you're trying to accomplish, and what precludes you from using UPDATE, but here goes:
CREATE TABLE #tempTable (col1, col2, col3, ...)
INSERT INTO #tempTable
SELECT
b.col1
, b.col2
, a.col3
, ...
FROM a
INNER JOIN b
ON a.col1 = b.col1
DELETE FROM b
WHERE col1 IN (SELECT col1 FROM a)
INSERT INTO b
SELECT
col1
, col2
, col3
, ...
FROM #TempTable
Which of course makes the bold assumption that Table a and b share a primary key, and that Table b doesn't have any constraint that would prevent deletion of matched rows. Please, provide some more detail and I'll update my answer accordingly.

sql replace null value with value with value in other column

I want to replace all values which has a NULL value with the the value in another column on the same row.
I have tried different sql statements without any success.
Regards

If you want to update, do something like this:
update t set col1 = col2
where col1 is null
If you just want to do selection, use most databases support coalesce:
select coalesce(col1, col2) from t;

If you want to Update the value from same column
UPDATE A
SET A.Col1 = A.Col2
From TableA A
Where A.Col1 IS NULL
If you want to update the value from Other table then Try this:
Update A
SET A.Column1 = B.Column1
From TableA A
INNER JOIN TableB B
ON A.SomeID = B.SameID
WHERE A.Column1 IS NULL
You can update the value by using join and update query.

SQL Error: ORA-00905: missing keyword, can someone please tel me whats wrong with the below merge statement

MERGE INTO table_a PARTITION (x) A
USING (SELECT distinct col1,col2 FROM table_b)b
ON (A.col1=B.col1(+) AND A.col2=B.col2(+))
WHEN MATCHED THEN
UPDATE SET col3='Y'
WHEN NOT MATCHED THEN
UPDATE SET col3='N';

The WHEN NOT MATCHED clause cannot perform an UPDATE - what rows is it supposed to update if it didn't find any?
If you want to update A depending on whether there's an existing row in B, one approach is to pull A into the merge query (this assumes your table A has a primary key PK):
MERGE INTO table_a PARTITION (x) tgt
USING (
SELECT A.PK, B.col1, B.col2
FROM table_a A
LEFT JOIN table_b b ON A.col1 = B.col1 AND A.col2 = B.col2) src
ON (src.pk = tgt.pk)
WHEN MATCHED THEN
UPDATE SET col3 = (CASE WHEN src.col1 IS NOT NULL THEN 'Y' ELSE 'N' END);

How do I UPDATE from a SELECT in SQL Server?

In SQL Server, it is possible to insert rows into a table with an INSERT.. SELECT statement:
INSERT INTO Table (col1, col2, col3)
SELECT col1, col2, col3
FROM other_table
WHERE sql = 'cool'
Is it also possible to update a table with SELECT? I have a temporary table containing the values and would like to update another table using those values. Perhaps something like this:
UPDATE Table SET col1, col2
SELECT col1, col2
FROM other_table
WHERE sql = 'cool'
WHERE Table.id = other_table.id

UPDATE
Table_A
SET
Table_A.col1 = Table_B.col1,
Table_A.col2 = Table_B.col2
FROM
Some_Table AS Table_A
INNER JOIN Other_Table AS Table_B
ON Table_A.id = Table_B.id
WHERE
Table_A.col3 = 'cool'

In SQL Server 2008 (or newer), use MERGE
MERGE INTO YourTable T
USING other_table S
ON T.id = S.id
AND S.tsql = 'cool'
WHEN MATCHED THEN
UPDATE
SET col1 = S.col1,
col2 = S.col2;
Alternatively:
MERGE INTO YourTable T
USING (
SELECT id, col1, col2
FROM other_table
WHERE tsql = 'cool'
) S
ON T.id = S.id
WHEN MATCHED THEN
UPDATE
SET col1 = S.col1,
col2 = S.col2;

UPDATE YourTable
SET Col1 = OtherTable.Col1,
Col2 = OtherTable.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) AS OtherTable
WHERE
OtherTable.ID = YourTable.ID

I'd modify Robin's excellent answer to the following:
UPDATE Table
SET Table.col1 = other_table.col1,
Table.col2 = other_table.col2
FROM
Table
INNER JOIN other_table ON Table.id = other_table.id
WHERE
Table.col1 != other_table.col1
OR Table.col2 != other_table.col2
OR (
other_table.col1 IS NOT NULL
AND Table.col1 IS NULL
)
OR (
other_table.col2 IS NOT NULL
AND Table.col2 IS NULL
)
Without a WHERE clause, you'll affect even rows that don't need to be affected, which could (possibly) cause index recalculation or fire triggers that really shouldn't have been fired.

One way
UPDATE t
SET t.col1 = o.col1,
t.col2 = o.col2
FROM
other_table o
JOIN
t ON t.id = o.id
WHERE
o.sql = 'cool'

Another possibility not mentioned yet is to just chuck the SELECT statement itself into a CTE and then update the CTE.
WITH CTE
AS (SELECT T1.Col1,
T2.Col1 AS _Col1,
T1.Col2,
T2.Col2 AS _Col2
FROM T1
JOIN T2
ON T1.id = T2.id
/*Where clause added to exclude rows that are the same in both tables
Handles NULL values correctly*/
WHERE EXISTS(SELECT T1.Col1,
T1.Col2
EXCEPT
SELECT T2.Col1,
T2.Col2))
UPDATE CTE
SET Col1 = _Col1,
Col2 = _Col2;
This has the benefit that it is easy to run the SELECT statement on its own first to sanity check the results, but it does requires you to alias the columns as above if they are named the same in source and target tables.
This also has the same limitation as the proprietary UPDATE ... FROM syntax shown in four of the other answers. If the source table is on the many side of a one-to-many join then it is undeterministic which of the possible matching joined records will be used in the Update (an issue that MERGE avoids by raising an error if there is an attempt to update the same row more than once).

For the record (and others searching like I was), you can do it in MySQL like this:
UPDATE first_table, second_table
SET first_table.color = second_table.color
WHERE first_table.id = second_table.foreign_id

Using alias:
UPDATE t
SET t.col1 = o.col1
FROM table1 AS t
INNER JOIN
table2 AS o
ON t.id = o.id

The simple way to do it is:
UPDATE
table_to_update,
table_info
SET
table_to_update.col1 = table_info.col1,
table_to_update.col2 = table_info.col2
WHERE
table_to_update.ID = table_info.ID

This may be a niche reason to perform an update (for example, mainly used in a procedure), or may be obvious to others, but it should also be stated that you can perform an update-select statement without using join (in case the tables you're updating between have no common field).
update
Table
set
Table.example = a.value
from
TableExample a
where
Table.field = *key value* -- finds the row in Table
AND a.field = *key value* -- finds the row in TableExample a

Here is another useful syntax:
UPDATE suppliers
SET supplier_name = (SELECT customers.name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id)
WHERE EXISTS (SELECT customers.name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id);
It checks if it is null or not by using "WHERE EXIST".

I add this only so you can see a quick way to write it so that you can check what will be updated before doing the update.
UPDATE Table
SET Table.col1 = other_table.col1,
Table.col2 = other_table.col2
--select Table.col1, other_table.col,Table.col2,other_table.col2, *
FROM Table
INNER JOIN other_table
ON Table.id = other_table.id

If you use MySQL instead of SQL Server, the syntax is:
UPDATE Table1
INNER JOIN Table2
ON Table1.id = Table2.id
SET Table1.col1 = Table2.col1,
Table1.col2 = Table2.col2

UPDATE from SELECT with INNER JOIN in SQL Database
Since there are too many replies of this post, which are most heavily up-voted, I thought I would provide my suggestion here too. Although the question is very interesting, I have seen in many forum sites and made a solution using INNER JOIN with screenshots.
At first, I have created a table named with schoolold and inserted few records with respect to their column names and execute it.
Then I executed SELECT command to view inserted records.
Then I created a new table named with schoolnew and similarly executed above actions on it.
Then, to view inserted records in it, I execute SELECT command.
Now, Here I want to make some changes in third and fourth row, to complete this action, I execute UPDATE command with INNER JOIN.
To view the changes I execute the SELECT command.
You can see how Third and Fourth records of table schoolold easily replaced with table schoolnew by using INNER JOIN with UPDATE statement.

And if you wanted to join the table with itself (which won't happen too often):
update t1 -- just reference table alias here
set t1.somevalue = t2.somevalue
from table1 t1 -- these rows will be the targets
inner join table1 t2 -- these rows will be used as source
on .................. -- the join clause is whatever suits you

Updating through CTE is more readable than the other answers here:
;WITH cte
AS (SELECT col1,col2,id
FROM other_table
WHERE sql = 'cool')
UPDATE A
SET A.col1 = B.col1,
A.col2 = B.col2
FROM table A
INNER JOIN cte B
ON A.id = B.id

The following example uses a derived table, a SELECT statement after the FROM clause, to return the old and new values for further updates:
UPDATE x
SET x.col1 = x.newCol1,
x.col2 = x.newCol2
FROM (SELECT t.col1,
t2.col1 AS newCol1,
t.col2,
t2.col2 AS newCol2
FROM [table] t
JOIN other_table t2
ON t.ID = t2.ID) x

If you are using SQL Server you can update one table from another without specifying a join and simply link the two from the where clause. This makes a much simpler SQL query:
UPDATE Table1
SET Table1.col1 = Table2.col1,
Table1.col2 = Table2.col2
FROM
Table2
WHERE
Table1.id = Table2.id

Consolidating all the different approaches here.
Select update
Update with a common table expression
Merge
Sample table structure is below and will update from Product_BAK to Product table.
Table Product
CREATE TABLE [dbo].[Product](
[Id] [int] IDENTITY(1, 1) NOT NULL,
[Name] [nvarchar](100) NOT NULL,
[Description] [nvarchar](100) NULL
) ON [PRIMARY]
Table Product_BAK
CREATE TABLE [dbo].[Product_BAK](
[Id] [int] IDENTITY(1, 1) NOT NULL,
[Name] [nvarchar](100) NOT NULL,
[Description] [nvarchar](100) NULL
) ON [PRIMARY]
1. Select update
update P1
set Name = P2.Name
from Product P1
inner join Product_Bak P2 on p1.id = P2.id
where p1.id = 2
2. Update with a common table expression
; With CTE as
(
select id, name from Product_Bak where id = 2
)
update P
set Name = P2.name
from product P inner join CTE P2 on P.id = P2.id
where P2.id = 2
3. Merge
Merge into product P1
using Product_Bak P2 on P1.id = P2.id
when matched then
update set p1.[description] = p2.[description], p1.name = P2.Name;
In this Merge statement, we can do insert if not finding a matching record in the target, but exist in the source and please find syntax:
Merge into product P1
using Product_Bak P2 on P1.id = P2.id;
when matched then
update set p1.[description] = p2.[description], p1.name = P2.Name;
WHEN NOT MATCHED THEN
insert (name, description)
values(p2.name, P2.description);

The other way is to use a derived table:
UPDATE t
SET t.col1 = a.col1
,t.col2 = a.col2
FROM (
SELECT id, col1, col2 FROM #tbl2) a
INNER JOIN #tbl1 t ON t.id = a.id
Sample data
DECLARE #tbl1 TABLE (id INT, col1 VARCHAR(10), col2 VARCHAR(10))
DECLARE #tbl2 TABLE (id INT, col1 VARCHAR(10), col2 VARCHAR(10))
INSERT #tbl1 SELECT 1, 'a', 'b' UNION SELECT 2, 'b', 'c'
INSERT #tbl2 SELECT 1, '1', '2' UNION SELECT 2, '3', '4'
UPDATE t
SET t.col1 = a.col1
,t.col2 = a.col2
FROM (
SELECT id, col1, col2 FROM #tbl2) a
INNER JOIN #tbl1 t ON t.id = a.id
SELECT * FROM #tbl1
SELECT * FROM #tbl2

UPDATE TQ
SET TQ.IsProcessed = 1, TQ.TextName = 'bla bla bla'
FROM TableQueue TQ
INNER JOIN TableComment TC ON TC.ID = TQ.TCID
WHERE TQ.IsProcessed = 0
To make sure you are updating what you want, select first
SELECT TQ.IsProcessed, 1 AS NewValue1, TQ.TextName, 'bla bla bla' AS NewValue2
FROM TableQueue TQ
INNER JOIN TableComment TC ON TC.ID = TQ.TCID
WHERE TQ.IsProcessed = 0

There is even a shorter method and it might be surprising for you:
Sample data set:
CREATE TABLE #SOURCE ([ID] INT, [Desc] VARCHAR(10));
CREATE TABLE #DEST ([ID] INT, [Desc] VARCHAR(10));
INSERT INTO #SOURCE VALUES(1,'Desc_1'), (2, 'Desc_2'), (3, 'Desc_3');
INSERT INTO #DEST VALUES(1,'Desc_4'), (2, 'Desc_5'), (3, 'Desc_6');
Code:
UPDATE #DEST
SET #DEST.[Desc] = #SOURCE.[Desc]
FROM #SOURCE
WHERE #DEST.[ID] = #SOURCE.[ID];

Use:
drop table uno
drop table dos
create table uno
(
uid int,
col1 char(1),
col2 char(2)
)
create table dos
(
did int,
col1 char(1),
col2 char(2),
[sql] char(4)
)
insert into uno(uid) values (1)
insert into uno(uid) values (2)
insert into dos values (1,'a','b',null)
insert into dos values (2,'c','d','cool')
select * from uno
select * from dos
EITHER:
update uno set col1 = (select col1 from dos where uid = did and [sql]='cool'),
col2 = (select col2 from dos where uid = did and [sql]='cool')
OR:
update uno set col1=d.col1,col2=d.col2 from uno
inner join dos d on uid=did where [sql]='cool'
select * from uno
select * from dos
If the ID column name is the same in both tables then just put the table name before the table to be updated and use an alias for the selected table, i.e.:
update uno set col1 = (select col1 from dos d where uno.[id] = d.[id] and [sql]='cool'),
col2 = (select col2 from dos d where uno.[id] = d.[id] and [sql]='cool')

In the accepted answer, after the:
SET
Table_A.col1 = Table_B.col1,
Table_A.col2 = Table_B.col2
I would add:
OUTPUT deleted.*, inserted.*
What I usually do is putting everything in a roll backed transaction and using the "OUTPUT": in this way I see everything that is about to happen. When I am happy with what I see, I change the ROLLBACK into COMMIT.
I usually need to document what I did, so I use the "results to Text" option when I run the roll-backed query and I save both the script and the result of the OUTPUT. (Of course this is not practical if I changed too many rows)

UPDATE table AS a
INNER JOIN table2 AS b
ON a.col1 = b.col1
INNER JOIN ... AS ...
ON ... = ...
SET ...
WHERE ...

The below solution works for a MySQL database:
UPDATE table1 a , table2 b
SET a.columname = 'some value'
WHERE b.columnname IS NULL ;

The other way to update from a select statement:
UPDATE A
SET A.col = A.col,B.col1 = B.col1
FROM first_Table AS A
INNER JOIN second_Table AS B ON A.id = B.id WHERE A.col2 = 'cool'

Option 1: Using Inner Join:
UPDATE
A
SET
A.col1 = B.col1,
A.col2 = B.col2
FROM
Some_Table AS A
INNER JOIN Other_Table AS B
ON A.id = B.id
WHERE
A.col3 = 'cool'
Option 2: Co related Sub query
UPDATE table
SET Col1 = B.Col1,
Col2 = B.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) B
WHERE
B.ID = table.ID

UPDATE table1
SET column1 = (SELECT expression1
FROM table2
WHERE conditions)
[WHERE conditions];
The syntax for the UPDATE statement when updating one table with data from another table in SQL Server.

It is important to point out, as others have, that MySQL or MariaDB use a different syntax. Also it supports a very convenient USING syntax (in contrast to T/SQL). Also INNER JOIN is synonymous with JOIN. Therefore the query in the original question would be best implemented in MySQL thusly:
UPDATE
Some_Table AS Table_A
JOIN
Other_Table AS Table_B USING(id)
SET
Table_A.col1 = Table_B.col1,
Table_A.col2 = Table_B.col2
WHERE
Table_A.col3 = 'cool'
I've not seen the a solution to the asked question in the other answers, hence my two cents.
(tested on PHP 7.4.0 MariaDB 10.4.10)

We Keep Coding

sql objective-c vba vb.net react-native apache vue.js tensorflow api pandas

Merge multiple tables into one table SQL Server - sql

Can you show the table Structure. you can use UNION ALL Operator follow this link. https://www.techonthenet.com/sql_server/union.php OR mixture of INNER JOIN with UPDATE statement combining the condition on WHERE clause

Related

Aster UPDATE Column Does Not Exist

How to update table without using update keyword

sql replace null value with value with value in other column

SQL Error: ORA-00905: missing keyword, can someone please tel me whats wrong with the below merge statement

How do I UPDATE from a SELECT in SQL Server?

Categories

Resources