grafana/docs/sources/panels/query-a-data-source/use-expressions-to-manipulate-data/write-an-expression.md

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/docs/grafana/latest/panels/query-a-data-source/use-expressions-to-manipulate-data/write-an-expression/ /docs/sources/panels/query-a-data-source/use-expressions-to-manipulate-data/write-an-expression/	Write an expression	20

Write an expression

If your data source supports them, then Grafana displays the Expression button and shows any existing expressions in the query editor list.

For more information about expressions, refer to [About expressions]({{< relref "about-expressions/" >}}).

Before you begin

• [Add a panel]({{< relref "../../working-with-panels/add-panel/" >}}).

To write an expression:

1. Open the panel.

2. Below the query, click Expression.

3. In the Operation field, select the type of expression you want to write.

   For more information about expression operations, refer to [About expressions]({{< relref "about-expressions/" >}}).

4. Write the expression.

5. Click Apply.