Function extract_using_from_upper

nodedb-sql/src/ddl_ast/parse/rls.rs:154–179

Fallback: extract predicate text from the uppercased SQL string when USING appears without space-separated parts matching (e.g. `USING(x=1)`).

(upper: &str)

/// Fallback: extract predicate text from the uppercased SQL string when
/// USING appears without space-separated parts matching (e.g. `USING(x=1)`).
fn extract_using_from_upper(upper: &str) -> String {
    let Some(start) = upper.find("USING") else {
        return String::new();
    };
    let after = &upper[start + 5..].trim_start();
    if after.starts_with('(') {
        let mut depth = 0usize;
        let mut end = 0;
        for (i, ch) in after.char_indices() {
            match ch {
                '(' => depth += 1,
                ')' => {
                    depth -= 1;
                    if depth == 0 {
                        end = i;
                        break;
                    }
                }
                _ => {}
            }
        }
        after[1..end].trim().to_string()
    } else {
        String::new()
    }
}