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
How to UPDATE from a SELECT in SQL Server? Answer #1:
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'
Update from a Select in SQL server- Answer #2:
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;
Query to Update from a Select in SQL server- Answer #3:
UPDATE YourTable
SET Col1 = OtherTable.Col1,
Col2 = OtherTable.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) AS OtherTable
WHERE
OtherTable.ID = YourTable.ID
Update from Select in SQL- Answer #4:
I’d modify the first 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.
Examples to update from select in SQL server- Answer #5:
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 nice 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”.
Answer #6:
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.
Hope you learned something from this post.
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