UPDATE

Modifies rows in a Primary Key table. In versions earlier than version 3.0, the UPDATE statement only supports simple syntax, such as UPDATE <table_name> SET <column_name>=<expression> WHERE <where_condition>. Starting from version 3.0, StarRocks enriches the syntax to support multi-table joins and common table expressions (CTEs). If you need to join the table to be updated with other tables in the database, you can reference these other tables in the FROM clause or CTE.

Usage notes

[ WITH <with_query> [, ...] ]
UPDATE <table_name>
SET <column_name> = <expression> [, ...]
[ FROM <from_item> [, ...] ]
WHERE <where_condition>

Parameters

with_query

One or more CTEs that can be referenced by name in an UPDATE statement. CTEs are temporary result sets that can improve the readability of complex statements.

table_name

The name of the table to be updated.

column_name

The name of the column to be updated. It cannot include the table name. For example, 'UPDATE t1 SET col = 1' is not valid.

expression

The expression that assigns new values to the column.

from_item

One or more other tables in the database. These tables can be joined with the table to be updated based on the condition specified in the WHERE clause. The values of the rows in the result set are used to update the values for the specified columns in the matched rows in the table to be updated. For example, if the FROM clause is FROM t1 WHERE t0.pk = t1.pk, StarRocks converts the table expression in the FROM clause to t0 JOIN t1 ON t0.pk=t1.pk when executing the UPDATE statement.

where_condition

The condition based on which you want to update rows. Only rows that meet the WHERE condition can be updated. This parameter is required, because it helps prevent you from accidentally updating the entire table. If you want to update the entire table, you can use 'WHERE true'.

Examples

For example, there are two tables employees and accounts in StarRocks. The table employees records employee information, and the table accounts records account information.

CREATE TABLE Employees (
    EmployeeID INT,
    Name VARCHAR(50),
    Salary DECIMAL(10, 2)
)
PRIMARY KEY (EmployeeID) 
DISTRIBUTED BY HASH (EmployeeID) BUCKETS 1
PROPERTIES ("replication_num" = "3");

INSERT INTO Employees VALUES
    (1, 'John Doe', 5000),
    (2, 'Jane Smith', 6000),
    (3, 'Robert Johnson', 5500),
    (4, 'Emily Williams', 4500),
    (5, 'Michael Brown', 7000);

If you need to give a 10% raise to all employees, you can execute the following statement:

UPDATE Employees
SET Salary = Salary * 1.1  -- Increase the salary by 10%.
WHERE true;

If you need to give a 10% raise to employees with salaries lower than the average salary, you can execute the following statement:

UPDATE Employees
SET Salary = Salary * 1.1   -- Increase the salary by 10%.
WHERE Salary < (SELECT AVG(Salary) FROM Employees);

You can also use a CTE to rewrite the above statement to improve readability.

WITH AvgSalary AS (
    SELECT AVG(Salary) AS AverageSalary
    FROM Employees
)
UPDATE Employees
SET Salary = Salary * 1.1   -- Increase the salary by 10%.
FROM AvgSalary
WHERE Employees.Salary < AvgSalary.AverageSalary;

Multi-table UPDATE

Create a table Accounts to record account information and insert three data rows into the table.

CREATE TABLE Accounts (
    Accounts_id BIGINT NOT NULL,
    Name VARCHAR(26) NOT NULL,
    Sales_person VARCHAR(50) NOT NULL
) 
PRIMARY KEY (Accounts_id)
DISTRIBUTED BY HASH (Accounts_id) BUCKETS 1
PROPERTIES ("replication_num" = "3");

INSERT INTO employees VALUES (1,100),(2,1000);

CREATE TABLE accounts 
(
    accounts_id BIGINT NOT NULL,
    name VARCHAR(26) NOT NULL,
    sales_person INT NOT NULL
) 
PRIMARY KEY (accounts_id)
DISTRIBUTED BY HASH(accounts_id) BUCKETS 1
PROPERTIES ("replication_num" = "3");

INSERT INTO accounts VALUES (1,'Acme Corporation',2),(2,'Acme Corporation',3),(3,'Corporation',3);

If you need to increase the sales count of salespersons that manage Acme Corporation's account in the employees table by 1, you can execute the following statement:

UPDATE employees
SET sales_count = sales_count + 1
FROM accounts
WHERE accounts.name = 'Acme Corporation'
   AND employees.id = accounts.sales_person;

You can also use a CTE to rewrite the above statement to improve readability.

WITH acme_accounts as (
    SELECT * from accounts
     WHERE accounts.name = 'Acme Corporation'
)
UPDATE employees SET sales_count = sales_count + 1
FROM acme_accounts
WHERE employees.id = acme_accounts.sales_person;