Select Query

Example 1: Select Data

In this example, we'll use the MySQL Execute function with the Type set to Select to get data from MySQL.

Add MySQL Execute Function

Start by adding the MySQL Execute function. Give it a Result Name and set the Type to Select.

Write the SQL Query

In the function configuration, write the SQL query you want to use to fetch data.

Assume we have a users table and want to retrieve x number of records. The users table schema looks like this:

CREATE TABLE `users` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `email` varchar(150) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL,
  `age` int unsigned NOT NULL,
  `activated` tinyint(1) NOT NULL DEFAULT '1',
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

Now write the following query:

SELECT id, name, email, activated FROM users LIMIT ?

Fill the Arguments

Now provide the required arguments for the query. Since we're using LIMIT ?, we need to supply how many records to fetch. For example, if you want to retrieve 5 users:

[5]

Define a Model for Returned Values

Next, we define a model (struct) that maps the returned SQL data to a usable object in the function.

We recommend defining models in reusable custom functions. This allows you to update a model in one place and automatically reflect changes across all references.

For simplicity, we’ll define the model inline in this example.

In the Model input:

Click Define to create a new struct.
Set a name, e.g., User.
Add your fields. These can include more than what's returned from the query, but must at least match the selected columns.

Check SqlRes

Map Struct Fields to SQL Query

After defining your model, you need to map the fields to the selected SQL columns using the Field Mapper input.

The order here must match the order of columns in your SQL query:

["Id", "Name", "Email", "Activated"]

Finally, set the Expected Result Set to 5 to allocate a list with enough space to store the results efficiently.

Check SqlRes

Use the Returned Result

The result is returned as either Res<SqlRes> or directly SqlRes if unwrapped.

It contains a Data field, which is a list of rows returned from the database.

To access a specific field, like the ID of the first user, use dot syntax:

selectRes1.Data.0.Id

Check Select

To easily select nested fields, use the UI helper:

Click the Select button next to the selectRes1 variable.
Click the Data field, then manually enter an index (e.g. 0) in the input box.
Click the field name (e.g. Id) from the list that appears.

You can insert ! symbol at end to force unwrap the result and access the value directly, without handling the Result wrapper.