# How to use SQL UPDATE

SQL `UPDATE` can be used to update **a table as a whole** or to make changes to selected entries. It relieves you of the tedious work of updating entries line by line, making it one of the most important tools in SQL.

## What is SQL `UPDATE`?

The **quality of databases and efficiency of queries** is closely related to how updated those [databases](https://www.ionos.co.uk/digitalguide/hosting/technical-matters/databases/) are. Incorrect, incomplete or outdated records can not only skew analyses and reports but also lead to weak points in data protection and performance. That’s why SQL `UPDATE` is such an important [SQL command](https://www.ionos.co.uk/digitalguide/server/configuration/sql-commands/) – it allows you to update, edit and correct data in selected tables and records.

Using SQL `UPDATE` to keep your data up to date helps to avoid inconsistencies, reduce errors in databases and optimise your **efficiency and performance**. The command can also be used with different data types, with scripts for automation and with other [SQL operators](https://www.ionos.co.uk/digitalguide/server/configuration/sql-operators/).

Tip You have limited knowledge of [SQL](https://www.ionos.co.uk/digitalguide/server/know-how/what-is-sql/) but want to learn more quickly? In our [introduction to SQL with examples](https://www.ionos.co.uk/digitalguide/server/configuration/sql-introduction-with-examples/) we explain the basics of SQL.

## What is the syntax of SQL `UPDATE`?

The basic syntax of SQL `UPDATE` looks as follows:

```sql
UPDATE  Table
SET  ColumnA  =  New_value1,  ColumnB  =  New_value2
WHERE  Condition
```

The following parameters can be used with it:

- `UPDATE`: Specifies which table you want to make updates in.
- `SET`: Specifies which column you want to update and which values you want to update them with.
- `WHERE`: [WHERE](https://www.ionos.co.uk/digitalguide/server/configuration/sql-where/) clauses allow you to define conditions that a column needs to meet to be updated. It is useful if you only want to update a subset of records.

## What is SQL `UPDATE` used for?

SQL `UPDATE` is useful for a variety of cases in which you need to **update data as simply as possible**. It’s particularly indispensable for database maintenance in situations such as:

- Correcting errors, inaccuracies or inconsistencies
- Updating master data, product information, contact details and prices
- Adjusting inventories or order/shipping status
- Updating financial data after transactions
- Marking or labelling customer or product data

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## Examples for SQL `UPDATE`

We’ll now take a look at two easy examples that show how SQL `UPDATE` is used in practice.

### Updating product data

In this example, we’ll work in a table called ‘Products’ and change ‘Makeup’ to ‘Hair & Makeup’ in the ‘Category’ column.

```sql
UPDATE  Products
SET  Category  =  'Hair & Makeup'
WHERE  Category  =  'Makeup'
```

### Updating employee data

In this example we’ll change the name of the department called ‘Finance’ to ‘Distribution and finance’:

```sql
SELECT  Employees
SET  Department  =  'Distribution and finance'
WHERE  Category  =  'Finance'
```

## What are the alternatives to SQL `UPDATE`?

In addition to `UPDATE`, there are a number of other SQL commands, statements and functions for changing and updating data:

- `MERGE`: Similar to `UPDATE`, `MERGE` can be used to change or adjust records in a target table based on a source table. Note that it’s not recommended to use `MERGE` if you are already using `UPDATE`, `INSERT` or `DELETE`, since `MERGE` essentially combines those functions. It can also recognise duplicates and can be combined with `JOIN` and subqueries.
- `INSERT` or `INSERT INTO … SELECT`: [SQL INSERT INTO SELECT](https://www.ionos.co.uk/digitalguide/server/configuration/sql-insert-into-select/) can be used to copy data from a source table into a target table or update records in a target table. You can use it to both merge data and change data in a target table. Similar to `MERGE` and in contrast to `UPDATE`, it does not require the use of a `WHERE` clause.
- `DELETE`: SQL DELETE allows you to delete a single record or several records.


This is a markdown version of: [https://www.ionos.co.uk/digitalguide/server/configuration/sql-update/](https://www.ionos.co.uk/digitalguide/server/configuration/sql-update/) for AI/LLM consumption.