diff --git a/server/services/store/mattermostauthlayer/mattermostauthlayer.go b/server/services/store/mattermostauthlayer/mattermostauthlayer.go
index 65d3b28d5..613964121 100644
--- a/server/services/store/mattermostauthlayer/mattermostauthlayer.go
+++ b/server/services/store/mattermostauthlayer/mattermostauthlayer.go
@@ -671,6 +671,11 @@ func (s *MattermostAuthLayer) baseUserQuery(showEmail, showName bool) sq.SelectB
 // they're open, regardless of the user membership.
 // Search is case-insensitive.
 func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePublicBoards bool) ([]*model.Board, error) {
+	// as we're joining three queries, we need to avoid numbered
+	// placeholders until the join is done, so we use the default
+	// question mark placeholder here
+	builder := s.getQueryBuilder().PlaceholderFormat(sq.Question)
+
 	var boardMembersWhere sq.Or
 	var channelMembersWhere sq.Or
 
@@ -692,7 +697,7 @@ func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePu
 		}
 	}
 
-	boardMembersQ := s.getQueryBuilder().
+	boardMembersQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards as b").
 		Join(s.tablePrefix + "board_members as bm on b.id=bm.board_id").
@@ -701,7 +706,7 @@ func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePu
 		}).
 		Where(boardMembersWhere)
 
-	teamMembersQ := s.getQueryBuilder().
+	teamMembersQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards as b").
 		Join("TeamMembers as tm on tm.teamid=b.team_id").
@@ -711,7 +716,7 @@ func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePu
 			"tm.deleteAt":   0,
 		})
 
-	channelMembersQ := s.getQueryBuilder().
+	channelMembersQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards as b").
 		Join("ChannelMembers as cm on cm.channelId=b.channel_id").
@@ -774,7 +779,23 @@ func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePu
 		unionQ = unionQ.Where(sq.Eq{"b.id": boardIDs})
 	}
 
-	rows, err := unionQ.Query()
+	unionSQL, unionArgs, err := unionQ.ToSql()
+	if err != nil {
+		return nil, fmt.Errorf("SearchBoardsForUser error getting unionSQL: %w", err)
+	}
+
+	// if we're using postgres or sqlite, we need to replace the
+	// question mark placeholder with the numbered dollar one, now
+	// that the full query is built
+	if s.dbType == model.PostgresDBType || s.dbType == model.SqliteDBType {
+		var rErr error
+		unionSQL, rErr = sq.Dollar.ReplacePlaceholders(unionSQL)
+		if rErr != nil {
+			return nil, fmt.Errorf("SearchBoardsForUser unable to replace unionSQL placeholders: %w", rErr)
+		}
+	}
+
+	rows, err := s.mmDB.Query(unionSQL, unionArgs...)
 	if err != nil {
 		s.logger.Error(`searchBoardsForUser ERROR`, mlog.Err(err))
 		return nil, err
@@ -789,7 +810,12 @@ func (s *MattermostAuthLayer) SearchBoardsForUser(term, userID string, includePu
 // they're open, regardless of the user membership.
 // Search is case-insensitive.
 func (s *MattermostAuthLayer) SearchBoardsForUserInTeam(teamID, term, userID string) ([]*model.Board, error) {
-	openBoardsQ := s.getQueryBuilder().
+	// as we're joining three queries, we need to avoid numbered
+	// placeholders until the join is done, so we use the default
+	// question mark placeholder here
+	builder := s.getQueryBuilder().PlaceholderFormat(sq.Question)
+
+	openBoardsQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards as b").
 		Where(sq.Eq{
@@ -798,7 +824,7 @@ func (s *MattermostAuthLayer) SearchBoardsForUserInTeam(teamID, term, userID str
 			"b.type":        model.BoardTypeOpen,
 		})
 
-	memberBoardsQ := s.getQueryBuilder().
+	memberBoardsQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards AS b").
 		Join(s.tablePrefix + "board_members AS bm on b.id = bm.board_id").
@@ -808,7 +834,7 @@ func (s *MattermostAuthLayer) SearchBoardsForUserInTeam(teamID, term, userID str
 			"bm.user_id":    userID,
 		})
 
-	channelMemberBoardsQ := s.getQueryBuilder().
+	channelMemberBoardsQ := builder.
 		Select(boardFields("b.")...).
 		From(s.tablePrefix + "boards AS b").
 		Join("ChannelMembers AS cm on cm.channelId = b.channel_id").
@@ -838,14 +864,12 @@ func (s *MattermostAuthLayer) SearchBoardsForUserInTeam(teamID, term, userID str
 
 	memberBoardsSQL, memberBoardsArgs, err := memberBoardsQ.ToSql()
 	if err != nil {
-		s.logger.Error(`searchBoardsForUser ERROR getting memberBoardsSQL`, mlog.Err(err))
-		return nil, err
+		return nil, fmt.Errorf("SearchBoardsForUserInTeam error getting memberBoardsSQL: %w", err)
 	}
 
 	channelMemberBoardsSQL, channelMemberBoardsArgs, err := channelMemberBoardsQ.ToSql()
 	if err != nil {
-		s.logger.Error(`searchBoardsForUser ERROR getting channelMemberBoardsSQL`, mlog.Err(err))
-		return nil, err
+		return nil, fmt.Errorf("SearchBoardsForUserInTeam error getting channelMemberBoardsSQL: %w", err)
 	}
 
 	unionQ := openBoardsQ.
@@ -853,9 +877,25 @@ func (s *MattermostAuthLayer) SearchBoardsForUserInTeam(teamID, term, userID str
 		Suffix(") UNION ("+memberBoardsSQL, memberBoardsArgs...).
 		Suffix(") UNION ("+channelMemberBoardsSQL+")", channelMemberBoardsArgs...)
 
-	rows, err := unionQ.Query()
+	unionSQL, unionArgs, err := unionQ.ToSql()
 	if err != nil {
-		s.logger.Error(`searchBoardsForUser ERROR`, mlog.Err(err))
+		return nil, fmt.Errorf("SearchBoardsForUserInTeam error getting unionSQL: %w", err)
+	}
+
+	// if we're using postgres or sqlite, we need to replace the
+	// question mark placeholder with the numbered dollar one, now
+	// that the full query is built
+	if s.dbType == model.PostgresDBType || s.dbType == model.SqliteDBType {
+		var rErr error
+		unionSQL, rErr = sq.Dollar.ReplacePlaceholders(unionSQL)
+		if rErr != nil {
+			return nil, fmt.Errorf("SearchBoardsForUserInTeam unable to replace unionSQL placeholders: %w", rErr)
+		}
+	}
+
+	rows, err := s.mmDB.Query(unionSQL, unionArgs...)
+	if err != nil {
+		s.logger.Error(`searchBoardsForUserInTeam ERROR`, mlog.Err(err))
 		return nil, err
 	}
 	defer s.CloseRows(rows)