From 8d1a7db6ea7cd4e8d9e2b38874477c12b99ffcd7 Mon Sep 17 00:00:00 2001
From: Chris Heller <chrisheller@users.noreply.github.com>
Date: Sun, 29 Dec 2019 08:41:18 -0800
Subject: [PATCH] Check pqntuples > 0 in getValue. Fixes #12973 (#12974)

---
 lib/impure/db_postgres.nim | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/impure/db_postgres.nim b/lib/impure/db_postgres.nim
index fde4db1196..57c61fa23f 100644
--- a/lib/impure/db_postgres.nim
+++ b/lib/impure/db_postgres.nim
@@ -441,8 +441,12 @@ proc getValue*(db: DbConn, query: SqlQuery,
   ## executes the query and returns the first column of the first row of the
   ## result dataset. Returns "" if the dataset contains no rows or the database
   ## value is NULL.
-  var x = pqgetvalue(setupQuery(db, query, args), 0, 0)
-  result = if isNil(x): "" else: $x
+  var res = setupQuery(db, query, args)
+  if pqntuples(res) > 0:
+    var x = pqgetvalue(res, 0, 0)
+    result = if isNil(x): "" else: $x
+  else:
+    result = ""
 
 proc getValue*(db: DbConn, stmtName: SqlPrepared,
                args: varargs[string, `$`]): string {.
@@ -450,8 +454,12 @@ proc getValue*(db: DbConn, stmtName: SqlPrepared,
   ## executes the query and returns the first column of the first row of the
   ## result dataset. Returns "" if the dataset contains no rows or the database
   ## value is NULL.
-  var x = pqgetvalue(setupQuery(db, stmtName, args), 0, 0)
-  result = if isNil(x): "" else: $x
+  var res = setupQuery(db, stmtName, args)
+  if pqntuples(res) > 0:
+    var x = pqgetvalue(res, 0, 0)
+    result = if isNil(x): "" else: $x
+  else:
+    result = ""
 
 proc tryInsertID*(db: DbConn, query: SqlQuery,
                   args: varargs[string, `$`]): int64 {.