join with conditions

Makefile

@@ -2,3 +2,6 @@ run:
 	go run ./cmd -o ./example/db ./example/schema.sql
 bench-select:
 	go test ./example -bench BenchmarkSelect -memprofile memprofile.out -cpuprofile profile.out
+
+test:
+	go test ./playground

playground/qry_select_test.go

@@ -60,7 +60,31 @@ func TestSelectWithHaving(t *testing.T) {
 	}
 }
 
-// BenchmarkSelect-12    	  668817	      1753 ns/op	    4442 B/op	      59 allocs/op
+func TestSelectWithJoin(t *testing.T) {
+	got := db.User.Select(user.Email, user.FirstName).
+		Join(db.UserSession, user.ID, usersession.UserID).
+		LeftJoin(db.BranchUser, user.ID, branchuser.UserID, pgm.Or(branchuser.RoleID.Eq("1"), branchuser.RoleID.Eq("2"))).
+		Where(
+			user.ID.Eq(3),
+			pgm.Or(
+				user.StatusID.Eq(4),
+				user.UpdatedAt.Eq(5),
+			),
+		).
+		Limit(10).
+		Offset(100).
+		String()
+
+	expected := "SELECT users.email, users.first_name " +
+		"FROM users JOIN user_sessions ON users.id = user_sessions.user_id " +
+		"LEFT JOIN branch_users ON users.id = branch_users.user_id AND (branch_users.role_id = $1 OR branch_users.role_id = $2) " +
+		"WHERE users.id = $3 AND (users.status_id = $4 OR users.updated_at = $5) " +
+		"LIMIT 10 OFFSET 100"
+	if expected != got {
+		t.Errorf("\nexpected: %q\ngot: %q", expected, got)
+	}
+}
+
 // BenchmarkSelect-12    	  638901	      1860 ns/op	    4266 B/op	      61 allocs/op
 func BenchmarkSelect(b *testing.B) {
 	for b.Loop() {

qry.go

@@ -21,10 +21,10 @@ type (
 
 	SelectClause interface {
 		// Join and Inner Join are same
-		Join(m Table, t1Field, t2Field Field) SelectClause
-		LeftJoin(m Table, t1Field, t2Field Field) SelectClause
-		RightJoin(m Table, t1Field, t2Field Field) SelectClause
-		FullJoin(m Table, t1Field, t2Field Field) SelectClause
+		Join(m Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause
+		LeftJoin(m Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause
+		RightJoin(m Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause
+		FullJoin(m Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause
 		CrossJoin(m Table) SelectClause
 		WhereClause
 		OrderByClause

qry_select.go

@@ -62,23 +62,46 @@ func (t Table) Select(field ...Field) SelectClause {
 	return qb
 }
 
-func (q *selectQry) Join(t Table, t1Field, t2Field Field) SelectClause {
-	q.join = append(q.join, "JOIN "+t.Name+" ON "+t1Field.String()+" = "+t2Field.String())
+func (q *selectQry) Join(t Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause {
+	return q.buildJoin(t, "JOIN", t1Field, t2Field, cond...)
+}
+
+func (q *selectQry) LeftJoin(t Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause {
+	return q.buildJoin(t, "LEFT JOIN", t1Field, t2Field, cond...)
+}
+
+func (q *selectQry) RightJoin(t Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause {
+	return q.buildJoin(t, "RIGHT JOIN", t1Field, t2Field, cond...)
+}
+
+func (q *selectQry) FullJoin(t Table, t1Field, t2Field Field, cond ...Conditioner) SelectClause {
+	return q.buildJoin(t, "FULL JOIN", t1Field, t2Field, cond...)
+}
+
+func (q *selectQry) buildJoin(t Table, joinKW string, t1Field, t2Field Field, cond ...Conditioner) SelectClause {
+	str := joinKW + " " + t.Name + " ON " + t1Field.String() + " = " + t2Field.String()
+	if len(cond) == 0 { // Join with no condition
+		q.join = append(q.join, str)
 		return q
 	}
 
-func (q *selectQry) LeftJoin(t Table, t1Field, t2Field Field) SelectClause {
-	q.join = append(q.join, "LEFT JOIN "+t.Name+" ON "+t1Field.String()+" = "+t2Field.String())
-	return q
+	// Join has condition(s)
+	sb := getSB()
+	defer putSB(sb)
+	sb.Grow(len(str) * 2)
+
+	sb.WriteString(str + " AND ")
+
+	var argIdx int
+	for i, c := range cond {
+		argIdx = len(q.args)
+		if i > 0 {
+			sb.WriteString(" AND ")
+		}
+		sb.WriteString(c.Condition(&q.args, argIdx))
 	}
 
-func (q *selectQry) RightJoin(t Table, t1Field, t2Field Field) SelectClause {
-	q.join = append(q.join, "RIGHT JOIN "+t.Name+" ON "+t1Field.String()+" = "+t2Field.String())
-	return q
-}
-
-func (q *selectQry) FullJoin(t Table, t1Field, t2Field Field) SelectClause {
-	q.join = append(q.join, "FULL JOIN "+t.Name+" ON "+t1Field.String()+" = "+t2Field.String())
+	q.join = append(q.join, sb.String())
 	return q
 }