The DuckDB command line interface (CLI) provides us with the ability to output query results in various formats. One of these formatting options is HTML.

This article shows you how to output your DuckDB query results as HTML tables, which can be useful when you need to include the results in web pages or documentation.

Checking the Current Mode

Here are two ways to check your current output mode.

The easiest way to check your current output mode is by using the .mode command:

.mode

Example output:

current output mode: table

My current output mode is table, which formats the results as a table using ASCII characters.

Another way to check the current output mode is by running a sample query to see the output format:

CREATE TABLE products(id INTEGER, name VARCHAR, price DECIMAL);
INSERT INTO products VALUES 
    (1, 'Widget', 19.99), 
    (2, 'Gadget', 24.99);
SELECT * FROM products;

Output:

+----+--------+--------+
| id |  name  | price  |
+----+--------+--------+
| 1  | Widget | 19.990 |
| 2  | Gadget | 24.990 |
+----+--------+--------+

We can see that the results are formatted as a table, but only as ASCII-art (not an HTML table).

Changing to HTML Mode

To switch to HTML output mode, use:

.mode html

Verifying the Change

Check the mode setting:

.mode

This will confirm that HTML mode is active:

current output mode: html

The mode is html as expected.

Now let’s run a query to see the HTML output:

SELECT * FROM products;

The output will now be formatted as an HTML table:

<tr><th>id</th>
<th>name</th>
<th>price</th>
</tr>
<tr><td>1</td>
<td>Widget</td>
<td>19.990</td>
</tr>
<tr><td>2</td>
<td>Gadget</td>
<td>24.990</td>
</tr>

The output has been returned in HTML. This is the HTML source code for a table. When the HTML code is run in a web browser, it is rendered as a table instead of the above markup code.

Notice that this is not a complete HTML table. HTML tables are defined with the <table> element (i.e., they start with <table> and end with </table>), with each row defined by the <tr> element, which in turn can have other elements to define each column (such as <th> for table header, and <td> for table data).

So the assumption is that you would need to insert the above output in between <table> and </table> tags, so that it looks something like this:

<table>
    <tr><th>id</th>
    <th>name</th>
    <th>price</th>
    </tr>
    <tr><td>1</td>
    <td>Widget</td>
    <td>19.990</td>
    </tr>
    <tr><td>2</td>
    <td>Gadget</td>
    <td>24.990</td>
    </tr>
</table>

You could also apply other attributes to the HTML elements, such as a style attribute to apply styles, etc. Anything like that would depend on your requirements (or the requirements of the business).

Reverting to the Previous Mode

To return to the previous output mode (or another of your choosing):

.mode duckbox

That changed the output mode to duckbox, which is the default mode in DuckDB.

Listing All Available Output Modes

To see all available output modes in DuckDB CLI:

.help mode

Output:

.mode MODE ?TABLE?       Set output mode
   MODE is one of:
     ascii     Columns/rows delimited by 0x1F and 0x1E
     box       Tables using unicode box-drawing characters
     csv       Comma-separated values
     column    Output in columns.  (See .width)
     duckbox   Tables with extensive features
     html      HTML <table> code
     insert    SQL insert statements for TABLE
     json      Results in a JSON array
     jsonlines Results in a NDJSON
     latex     LaTeX tabular environment code
     line      One value per line
     list      Values delimited by "|"
     markdown  Markdown table format
     quote     Escape answers as for SQL
     table     ASCII-art table
     tabs      Tab-separated values
     tcl       TCL list elements
     trash     No output

Each mode has its own use cases, for example:

• html for web integration
• csv for spreadsheet compatibility
• json for API responses
• markdown for documentation
• insert for generating SQL INSERT statements
• ndjson for streaming data processing

The HTML mode is particularly useful when you need to:

• Generate content for web pages
• Create HTML email reports
• Produce documentation with formatted tables
• Share query results that need to be embedded in web-based platforms