Remove Select* functions other than SelectOne (#14)

The deleted functions had the unfortunate quirk that they would return
`nil, nil` if there were no results, where `SelectOne` returns `nil,
sql.ErrNoRows`. This created confusion about error handling.

Boulder only used one of these functions, `SelectNullInt`, and that is
being replaced by `SelectOne`.

Deletions (including initial test cleanup) implemented by Claude based
on the prompt "Please delete these functions: <list of functions>."

I updated TestSelectVal to maintain the original spirit. I had to add a
new row containing nulls for the various fields, because many of the
existing test cases were testing for "no rows found" as opposed to "null
values." Now we test both of those.

Author: jsha

db.go

@@ -624,90 +624,6 @@ func (m *DbMap) ExecContext(ctx context.Context, query string, args ...interface
 	return maybeExpandNamedQueryAndExec(ctx, m, query, args...)
 }
 
-// SelectInt is a convenience wrapper around the borp.SelectInt function
-func (m *DbMap) SelectInt(ctx context.Context, query string, args ...interface{}) (int64, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return 0, err
-	}
-
-	return SelectInt(ctx, m, query, args...)
-}
-
-// SelectNullInt is a convenience wrapper around the borp.SelectNullInt function
-func (m *DbMap) SelectNullInt(ctx context.Context, query string, args ...interface{}) (sql.NullInt64, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return sql.NullInt64{}, err
-	}
-
-	return SelectNullInt(ctx, m, query, args...)
-}
-
-// SelectFloat is a convenience wrapper around the borp.SelectFloat function
-func (m *DbMap) SelectFloat(ctx context.Context, query string, args ...interface{}) (float64, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return 0, err
-	}
-
-	return SelectFloat(ctx, m, query, args...)
-}
-
-// SelectNullFloat is a convenience wrapper around the borp.SelectNullFloat function
-func (m *DbMap) SelectNullFloat(ctx context.Context, query string, args ...interface{}) (sql.NullFloat64, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return sql.NullFloat64{}, err
-	}
-
-	return SelectNullFloat(ctx, m, query, args...)
-}
-
-// SelectStr is a convenience wrapper around the borp.SelectStr function
-func (m *DbMap) SelectStr(ctx context.Context, query string, args ...interface{}) (string, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return "", err
-	}
-
-	return SelectStr(ctx, m, query, args...)
-}
-
-// SelectNullStr is a convenience wrapper around the borp.SelectNullStr function
-func (m *DbMap) SelectNullStr(ctx context.Context, query string, args ...interface{}) (sql.NullString, error) {
-	if m.ExpandSliceArgs {
-		expandSliceArgs(&query, args...)
-	}
-
-	args, err := m.convertArgs(args...)
-	if err != nil {
-		return sql.NullString{}, err
-	}
-
-	return SelectNullStr(ctx, m, query, args...)
-}
-
 // SelectOne is a convenience wrapper around the borp.SelectOne function
 func (m *DbMap) SelectOne(ctx context.Context, holder interface{}, query string, args ...interface{}) error {
 	if m.ExpandSliceArgs {

gorp.go

@@ -70,12 +70,6 @@ type SqlExecutor interface {
 	Update(ctx context.Context, list ...interface{}) (int64, error)
 	Delete(ctx context.Context, list ...interface{}) (int64, error)
 	Select(ctx context.Context, i interface{}, query string, args ...interface{}) ([]interface{}, error)
-	SelectInt(ctx context.Context, query string, args ...interface{}) (int64, error)
-	SelectNullInt(ctx context.Context, query string, args ...interface{}) (sql.NullInt64, error)
-	SelectFloat(ctx context.Context, query string, args ...interface{}) (float64, error)
-	SelectNullFloat(ctx context.Context, query string, args ...interface{}) (sql.NullFloat64, error)
-	SelectStr(ctx context.Context, query string, args ...interface{}) (string, error)
-	SelectNullStr(ctx context.Context, query string, args ...interface{}) (sql.NullString, error)
 	SelectOne(ctx context.Context, holder interface{}, query string, args ...interface{}) error
 
 	// These method signatures are shared with *sql.DB.