The UPDATE
statement updates rows in a table.
If you update a row that contains a column referenced by a foreign key constraint and has an ON UPDATE
action, all of the dependent rows will also be updated.
Required privileges
The user must have the SELECT
and UPDATE
privileges on the table.
Synopsis
Parameters
Parameter | Description |
---|---|
common_table_expr |
See Common Table Expressions. |
table_name |
The name of the table that contains the rows you want to update. |
AS table_alias_name |
An alias for the table name. When an alias is provided, it completely hides the actual table name. |
column_name |
The name of the column whose values you want to update. |
a_expr |
The new value you want to use, the aggregate function you want to perform, or the scalar expression you want to use. |
DEFAULT |
To fill columns with their default values, use DEFAULT VALUES in place of a_expr . To fill a specific column with its default value, leave the value out of the a_expr or use DEFAULT at the appropriate position. |
column_name |
The name of a column to update. |
select_stmt |
A selection query. Each value must match the data type of its column on the left side of = . |
WHERE a_expr |
a_expr must be a scalar expression that returns Boolean values using columns (e.g., <column> = <value> ). Update rows that return TRUE .Without a WHERE clause in your statement, UPDATE updates all rows in the table. |
sort_clause |
An ORDER BY clause. See Ordering Query Results for more details. |
limit_clause |
A LIMIT clause. See Limiting Query Results for more details. |
RETURNING target_list |
Return values based on rows updated, where target_list can be specific column names from the table, * for all columns, or computations using scalar expressions. To return nothing in the response, not even the number of rows updated, use RETURNING NOTHING . |
Examples
Update a single column in a single row
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 4000.0 | Julian |
| 3 | 8700.0 | Dario |
| 4 | 3400.0 | Nitin |
+----+----------+----------+
(4 rows)
> UPDATE accounts SET balance = 5000.0 WHERE id = 2;
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 5000.0 | Julian |
| 3 | 8700.0 | Dario |
| 4 | 3400.0 | Nitin |
+----+----------+----------+
(4 rows)
Update multiple columns in a single row
> UPDATE accounts SET (balance, customer) = (9000.0, 'Kelly') WHERE id = 2;
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 9000.0 | Kelly |
| 3 | 8700.0 | Dario |
| 4 | 3400.0 | Nitin |
+----+----------+----------+
(4 rows)
> UPDATE accounts SET balance = 6300.0, customer = 'Stanley' WHERE id = 3;
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 9000.0 | Kelly |
| 3 | 6300.0 | Stanley |
| 4 | 3400.0 | Nitin |
+----+----------+----------+
(4 rows)
Update using SELECT
statement
> UPDATE accounts SET (balance, customer) =
(SELECT balance, customer FROM accounts WHERE id = 2)
WHERE id = 4;
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 9000.0 | Kelly |
| 3 | 6300.0 | Stanley |
| 4 | 9000.0 | Kelly |
+----+----------+----------+
(4 rows)
Update with default values
> UPDATE accounts SET balance = DEFAULT where customer = 'Stanley';
> SELECT * FROM accounts;
+----+----------+----------+
| id | balance | customer |
+----+----------+----------+
| 1 | 10000.50 | Ilya |
| 2 | 9000.0 | Kelly |
| 3 | NULL | Stanley |
| 4 | 9000.0 | Kelly |
+----+----------+----------+
(4 rows)
Update all rows
If you do not use the WHERE
clause to specify the rows to be updated, the values for all rows will be updated.
> UPDATE accounts SET balance = 5000.0;
> SELECT * FROM accounts;
+----+---------+----------+
| id | balance | customer |
+----+---------+----------+
| 1 | 5000.0 | Ilya |
| 2 | 5000.0 | Kelly |
| 3 | 5000.0 | Stanley |
| 4 | 5000.0 | Kelly |
+----+---------+----------+
(4 rows)
Update and return values
In this example, the RETURNING
clause returns the id
value of the row updated. The language-specific versions assume that you have installed the relevant client drivers.
RETURNING
mirrors the behavior of MySQL's last_insert_id()
function.query()
method for statements that return results and an exec()
method for statements that do not (e.g., Go), it's likely necessary to use the query()
method for UPDATE
statements with RETURNING
.> UPDATE accounts SET balance = DEFAULT WHERE id = 1 RETURNING id;
+----+
| id |
+----+
| 1 |
+----+
(1 row)
# Import the driver.
import psycopg2
# Connect to the "bank" database.
conn = psycopg2.connect(
database='bank',
user='root',
host='localhost',
port=26257
)
# Make each statement commit immediately.
conn.set_session(autocommit=True)
# Open a cursor to perform database operations.
cur = conn.cursor()
# Update a row in the "accounts" table
# and return the "id" value.
cur.execute(
'UPDATE accounts SET balance = DEFAULT WHERE id = 1 RETURNING id'
)
# Print out the returned value.
rows = cur.fetchall()
print('ID:')
for row in rows:
print([str(cell) for cell in row])
# Close the database connection.
cur.close()
conn.close()
The printed value would look like:
ID:
['1']
# Import the driver.
require 'pg'
# Connect to the "bank" database.
conn = PG.connect(
user: 'root',
dbname: 'bank',
host: 'localhost',
port: 26257
)
# Update a row in the "accounts" table
# and return the "id" value.
conn.exec(
'UPDATE accounts SET balance = DEFAULT WHERE id = 1 RETURNING id'
) do |res|
# Print out the returned value.
puts "ID:"
res.each do |row|
puts row
end
end
# Close communication with the database.
conn.close()
The printed value would look like:
ID:
{"id"=>"1"}
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/lib/pq"
)
func main() {
//Connect to the "bank" database.
db, err := sql.Open(
"postgres",
"postgresql://root@localhost:26257/bank?sslmode=disable"
)
if err != nil {
log.Fatal("error connecting to the database: ", err)
}
// Update a row in the "accounts" table
// and return the "id" value.
rows, err := db.Query(
"UPDATE accounts SET balance = DEFAULT WHERE id = 1 RETURNING id",
)
if err != nil {
log.Fatal(err)
}
// Print out the returned value.
defer rows.Close()
fmt.Println("ID:")
for rows.Next() {
var id int
if err := rows.Scan(&id); err != nil {
log.Fatal(err)
}
fmt.Printf("%d\n", id)
}
}
The printed value would look like:
ID:
1
var async = require('async');
// Require the driver.
var pg = require('pg');
// Connect to the "bank" database.
var config = {
user: 'root',
host: 'localhost',
database: 'bank',
port: 26257
};
pg.connect(config, function (err, client, done) {
// Closes communication with the database and exits.
var finish = function () {
done();
process.exit();
};
if (err) {
console.error('could not connect to cockroachdb', err);
finish();
}
async.waterfall([
function (next) {
// Update a row in the "accounts" table
// and return the "id" value.
client.query(
`UPDATE accounts SET balance = DEFAULT WHERE id = 1 RETURNING id`,
next
);
}
],
function (err, results) {
if (err) {
console.error('error updating and selecting from accounts', err);
finish();
}
// Print out the returned value.
console.log('ID:');
results.rows.forEach(function (row) {
console.log(row);
});
finish();
});
});
The printed value would like:
ID:
{ id: '1' }