Composable SQL templates

If I have a WHERE clause to conditionally include in the query, it would be nice to do something like
```ts
const whereClause = condition ? sql`name = ${name}` : sql`TRUE`
return db.query(sql`SELECT * FROM "foo" WHERE ${whereClause}`)
```
or even
```ts
const whereClause = condition ? sql`WHERE name = ${name}` : ''
return db.query(sql`SELECT * FROM "foo" ${whereClause}`)
```
Thoughts?