Function orderTerms

dialect/sql/sqlgraph/graph.go:438–501

(q, join *sql.Selector, ts []sql.OrderTerm)

}

func orderTerms(q, join *sql.Selector, ts []sql.OrderTerm) {
	for _, t := range ts {
		t := t
		var (
			// Order by column or expression.
			orderC string
			orderX func(*sql.Selector) sql.Querier
			// Order by options.
			desc, nullsfirst, nullslast bool
		)
		switch t := t.(type) {
		case *sql.OrderFieldTerm:
			f := t.Field
			if t.As != "" {
				f = t.As
			}
			orderC = join.C(f)
			if t.Selected {
				q.AppendSelect(orderC)
			}
			desc = t.Desc
			nullsfirst = t.NullsFirst
			nullslast = t.NullsLast
		case *sql.OrderExprTerm:
			if t.As != "" {
				orderC = join.C(t.As)
				if t.Selected {
					q.AppendSelect(orderC)
				}
			} else {
				orderX = t.Expr
			}
			desc = t.Desc
			nullsfirst = t.NullsFirst
			nullslast = t.NullsLast
		default:
			continue
		}
		q.OrderExprFunc(func(b *sql.Builder) {
			// Write the ORDER BY term.
			switch {
			case orderC != "":
				b.WriteString(orderC)
			case orderX != nil:
				b.Join(orderX(join))
			}
			// Unlike MySQL and SQLite, NULL values sort as if larger than any other value. Therefore,
			// we need to explicitly order NULLs first on ASC and last on DESC unless specified otherwise.
			switch normalizePG := b.Dialect() == dialect.Postgres && !nullsfirst && !nullslast; {
			case normalizePG && desc:
				b.WriteString(" DESC NULLS LAST")
			case normalizePG:
				b.WriteString(" NULLS FIRST")
			case desc:
				b.WriteString(" DESC")
			}
			if nullsfirst {
				b.WriteString(" NULLS FIRST")