write a JS function to parse SQL statement to GraphQL
Converting SQL to GraphQL is not a simple process as the two languages have significant differences in structure and syntax. There are also many different ways that a SQL query can be represented in GraphQL, depending on the desired output.

However, there are libraries and tools available that can assist with this conversion. One such tool is the graphql-sql-bridge library, which provides a simple interface for translating SQL queries to GraphQL.

Here's an example of how to use the graphql-sql-bridge library to convert a SQL statement to a GraphQL query:
```
const { SqlToGraphql } = require('graphql-sql-bridge');

const sql = 'SELECT * FROM users WHERE age > 18';

const gql = SqlToGraphql.getGqlQuery(sql, 'User');

console.log(gql);
```
In this example, we first import the SqlToGraphql class from the graphql-sql-bridge library. We then define a SQL statement to be converted to GraphQL, which selects all users where age is greater than 18.

Next, we call the getGqlQuery method on the SqlToGraphql object, passing in the SQL statement and the name of the GraphQL object we want to create (User in this case).

The getGqlQuery method returns a string containing the corresponding GraphQL query for the given SQL statement.

It's important to note that this is just one example of how to convert SQL to GraphQL using a library. The resulting GraphQL query may need to be modified depending on the specific use case and desired output.
Could you make a function that can do that same conversion, but without using a library? Just one condition and no joins is fine.