two How do I UPDATE from a SELECT in SQL Server?
update table from another database sql server (24)
In SQL Server, it's possible to insert into a table using a SELECT statement:
INSERT INTO Table (col1, col2, col3)
SELECT col1, col2, col3
FROM other_table
WHERE sql = 'cool'
Is it also possible to update via a 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
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
declare @tblStudent table (id int,name varchar(300))
declare @tblMarks table (std_id int,std_name varchar(300),subject varchar(50),marks int)
insert into @tblStudent Values (1,'Abdul')
insert into @tblStudent Values(2,'Rahim')
insert into @tblMarks Values(1,'','Math',50)
insert into @tblMarks Values(1,'','History',40)
insert into @tblMarks Values(2,'','Math',30)
insert into @tblMarks Values(2,'','history',80)
select * from @tblMarks
update m
set m.std_name=s.name
from @tblMarks as m
left join @tblStudent as s on s.id=m.std_id
select * from @tblMarks
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
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'
UPDATE table AS a
INNER JOIN table2 AS b
ON a.col1 = b.col1
INNER JOIN ... AS ...
ON ... = ...
SET ...
WHERE ...
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
Using alias:
UPDATE t
SET t.col1 = o.col1
FROM table1 AS t
INNER JOIN
table2 AS o
ON t.id = o.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
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).
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".
You can use from this for update in sql server
UPDATE
T1
SET
T1.col1 = T2.col1,
T1.col2 = T2.col2
FROM
Table1 AS T1
INNER JOIN Table2 AS T2
ON T1.id = T2.id
WHERE
T1.col3 = 'cool'
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
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 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.
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
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
Consolidating all the different approaches here.
- Select update
- Update with a common table expression
- Merge
Sample table structure are below and will update from Product_BAK to Product table.
Product
CREATE TABLE [dbo].[Product](
[Id] [int] IDENTITY(1, 1) NOT NULL,
[Name] [nvarchar](100) NOT NULL,
[Description] [nvarchar](100) NULL
) ON [PRIMARY]
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 the Merge statement, we can do inset if not finding a matching record in the target, but exist in the source and please find the 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);
UPDATE table
SET Col1 = i.Col1,
Col2 = i.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) i
WHERE
i.ID = table.ID
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'
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
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.
In SQL Server 2008 (or better), 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
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'
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
