v0.13.0 — Type-Safe Scalar Subqueries and Column Comparison

New Features

SelectSub — Type-Safe Scalar Subqueries in SELECT

No more raw SQL for correlated subqueries. Use the builder API:

// Before: raw SQL (not type-safe)
db.Select("id", "name").
    SelectExpr("(SELECT COUNT(*) FROM orders WHERE orders.user_id = users.id) AS order_count").
    From("users")

// After: type-safe builder API
sub := db.Select("COUNT(*)").From("orders").
    Where(relica.EqCol("orders.user_id", "users.id"))
db.Select("id", "name").
    SelectSub(sub.AsExpression(), "order_count").
    From("users")

EqCol — Column-to-Column Comparison

Proper identifier quoting for both sides:

relica.EqCol("o.user_id", "u.id")
// PostgreSQL: "o"."user_id" = "u"."id"
// MySQL:      `o`.`user_id` = `u`.`id`

Also: NotEqCol, GreaterThanCol, LessThanCol.

Testing

21 new test functions (488 lines) covering all dialects, correlated subqueries, parameter ordering, and the full pattern from issue #31.

---

Full Changelog: v0.12.1...v0.13.0