src/database/sql/sql.go | 2 +-

diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index 8f5588ed2680886be6766e68d0feb8b77e5d9e29..719be91043b671fcdb3b0cafb487fbb427b1662b 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -1070,7 +1070,7 @@ 			db.mu.Unlock()
 			select {
 			default:
 			case ret, ok := <-req:
-				if ok {
+				if ok && ret.conn != nil {
 					db.putConn(ret.conn, ret.err, false)
 				}
 			}