Good day, im having trouble in understanding how to pass arguments to js functions at my sqlx queries, for example I have the following sqlx file where I have a simple function called addOne(number):
Solved! Go to Solution.
Your JavaScript block executes before any SQL. This phase is dedicated to preparing and manipulating parts of the SQL query that will be executed.
c.id
) are inaccessible during this phase since the SQL query hasn't run yet.Dataform combines the output of your JavaScript (e.g., constants, dynamic SQL snippets) with your SQL template to construct the final query.
The "c is not defined" Error
This error arises when you attempt to pass a SQL column alias (like c.id
) directly into a JavaScript function. Remember, JavaScript runs before the SQL query, so it doesn't recognize these aliases yet.
Solution: Dynamic SQL Generation with JavaScript
The workaround is to use JavaScript for dynamically generating SQL expressions based on the available columns:
config { type: "view" }
js {
const tableName = "my-project.my-dataset.cars";
// Function to generate a SQL expression
function addOne(colName) {
return `(${colName} + 1)`;
}
}
SELECT c.id, c.color, ${addOne('c.id')} AS id_plus_one FROM ${tableName} AS c
Explanation:
addOne
function now returns a SQL expression string (like (c.id + 1)
) instead of attempting to compute it with JavaScript.AS id_plus_one
provides a meaningful name for the resulting calculated column.Example Output:
id | color | id_plus_one |
---|---|---|
1 | red | 2 |
2 | blue | 3 |
3 | green | 4 |
Advanced JavaScript Functions
You can create more sophisticated functions following this pattern:
function calculateValue(colName, operation) {
return `CASE WHEN ${colName} IS NULL THEN NULL ELSE ${colName} ${operation} 1 END`;
}
Use it like this:
${calculateValue('c.id', '-')}
(for subtraction)${calculateValue('c.price', '*')}
(for multiplication)Best Practices & Tips
ref()
, self()
) for efficient referencing of other tables and views..js
files and include them in your SQLX files for better organization.
Your JavaScript block executes before any SQL. This phase is dedicated to preparing and manipulating parts of the SQL query that will be executed.
c.id
) are inaccessible during this phase since the SQL query hasn't run yet.Dataform combines the output of your JavaScript (e.g., constants, dynamic SQL snippets) with your SQL template to construct the final query.
The "c is not defined" Error
This error arises when you attempt to pass a SQL column alias (like c.id
) directly into a JavaScript function. Remember, JavaScript runs before the SQL query, so it doesn't recognize these aliases yet.
Solution: Dynamic SQL Generation with JavaScript
The workaround is to use JavaScript for dynamically generating SQL expressions based on the available columns:
config { type: "view" }
js {
const tableName = "my-project.my-dataset.cars";
// Function to generate a SQL expression
function addOne(colName) {
return `(${colName} + 1)`;
}
}
SELECT c.id, c.color, ${addOne('c.id')} AS id_plus_one FROM ${tableName} AS c
Explanation:
addOne
function now returns a SQL expression string (like (c.id + 1)
) instead of attempting to compute it with JavaScript.AS id_plus_one
provides a meaningful name for the resulting calculated column.Example Output:
id | color | id_plus_one |
---|---|---|
1 | red | 2 |
2 | blue | 3 |
3 | green | 4 |
Advanced JavaScript Functions
You can create more sophisticated functions following this pattern:
function calculateValue(colName, operation) {
return `CASE WHEN ${colName} IS NULL THEN NULL ELSE ${colName} ${operation} 1 END`;
}
Use it like this:
${calculateValue('c.id', '-')}
(for subtraction)${calculateValue('c.price', '*')}
(for multiplication)Best Practices & Tips
ref()
, self()
) for efficient referencing of other tables and views..js
files and include them in your SQLX files for better organization.
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