Add type-inferred queryValueOrDefault overload

async_postgres/pg_client.nim

@@ -1313,6 +1313,25 @@ proc queryValueOrDefault*[T](
     return default
   return row.get(0, T)
 
+proc queryValueOrDefault*[T](
+    conn: PgConnection,
+    sql: string,
+    params: seq[PgParam] = @[],
+    default: T,
+    timeout: Duration = ZeroDuration,
+): Future[T] {.async.} =
+  ## Execute a query and return the first column of the first row as `T`,
+  ## inferring `T` from `default`.
+  ## Returns `default` if no rows or the value is NULL.
+  ## Supported types: int32, int64, float64, bool, string.
+  let qr = await conn.query(sql, params, timeout = timeout)
+  if qr.rowCount == 0:
+    return default
+  let row = initRow(qr.data, 0)
+  if row.isNull(0):
+    return default
+  return row.get(0, T)
+
 proc queryExists*(
     conn: PgConnection,
     sql: string,

async_postgres/pg_pool.nim

@@ -866,6 +866,24 @@ proc queryValueOrDefault*[T](
     return default
   return row.get(0, T)
 
+proc queryValueOrDefault*[T](
+    pool: PgPool,
+    sql: string,
+    params: seq[PgParam] = @[],
+    default: T,
+    timeout: Duration = ZeroDuration,
+): Future[T] {.async.} =
+  ## Execute a query and return the first column of the first row as `T`,
+  ## inferring `T` from `default`.
+  ## Returns `default` if no rows or the value is NULL.
+  let qr = await pool.query(sql, params, timeout = timeout)
+  if qr.rowCount == 0:
+    return default
+  let row = initRow(qr.data, 0)
+  if row.isNull(0):
+    return default
+  return row.get(0, T)
+
 proc queryExists*(
     pool: PgPool,
     sql: string,

async_postgres/pg_pool_cluster.nim

@@ -292,6 +292,14 @@ clusterForwards("read"):
     timeout: Duration = ZeroDuration,
   ): Future[T]
 
+  proc readQueryValueOrDefault*[T](
+    cluster: PgPoolCluster,
+    sql: string,
+    params: seq[PgParam] = @[],
+    default: T,
+    timeout: Duration = ZeroDuration,
+  ): Future[T]
+
   proc readQueryExists*(
     cluster: PgPoolCluster,
     sql: string,
@@ -402,6 +410,14 @@ clusterForwards("write"):
     timeout: Duration = ZeroDuration,
   ): Future[T]
 
+  proc writeQueryValueOrDefault*[T](
+    cluster: PgPoolCluster,
+    sql: string,
+    params: seq[PgParam] = @[],
+    default: T,
+    timeout: Duration = ZeroDuration,
+  ): Future[T]
+
   proc writeQueryExists*(
     cluster: PgPoolCluster,
     sql: string,

async_postgres/pg_sql.nim

@@ -353,6 +353,10 @@ sqlQueryForwards:
     timeout: Duration = ZeroDuration,
   ): untyped
 
+  proc queryValueOrDefault*[T](
+    conn: PgConnection, sq: SqlQuery, default: T, timeout: Duration = ZeroDuration
+  ): untyped
+
   proc queryExists*(
     conn: PgConnection, sq: SqlQuery, timeout: Duration = ZeroDuration
   ): untyped
@@ -453,6 +457,10 @@ sqlQueryForwards:
     timeout: Duration = ZeroDuration,
   ): untyped
 
+  proc queryValueOrDefault*[T](
+    pool: PgPool, sq: SqlQuery, default: T, timeout: Duration = ZeroDuration
+  ): untyped
+
   proc queryExists*(
     pool: PgPool, sq: SqlQuery, timeout: Duration = ZeroDuration
   ): untyped
@@ -533,6 +541,10 @@ sqlQueryForwards:
     timeout: Duration = ZeroDuration,
   ): untyped
 
+  proc readQueryValueOrDefault*[T](
+    cluster: PgPoolCluster, sq: SqlQuery, default: T, timeout: Duration = ZeroDuration
+  ): untyped
+
   proc readQueryExists*(
     cluster: PgPoolCluster, sq: SqlQuery, timeout: Duration = ZeroDuration
   ): untyped
@@ -614,6 +626,10 @@ sqlQueryForwards:
     timeout: Duration = ZeroDuration,
   ): untyped
 
+  proc writeQueryValueOrDefault*[T](
+    cluster: PgPoolCluster, sq: SqlQuery, default: T, timeout: Duration = ZeroDuration
+  ): untyped
+
   proc writeQueryExists*(
     cluster: PgPoolCluster, sq: SqlQuery, timeout: Duration = ZeroDuration
   ): untyped

tests/test_e2e.nim

@@ -5075,6 +5075,17 @@ suite "E2E: Convenience Query Methods":
 
     waitFor t()
 
+  test "queryValueOrDefault infers type from default":
+    proc t() {.async.} =
+      let conn = await connect(plainConfig())
+      let val = await conn.queryValueOrDefault("SELECT 1 WHERE false", default = -1'i64)
+      doAssert val == -1'i64
+      let val2 = await conn.queryValueOrDefault("SELECT 42", default = 0'i32)
+      doAssert val2 == 42'i32
+      await conn.close()
+
+    waitFor t()
+
   test "queryValueOpt returns some on value":
     proc t() {.async.} =
       let conn = await connect(plainConfig())
@@ -5337,6 +5348,17 @@ suite "E2E: Convenience Query Methods":
 
     waitFor t()
 
+  test "pool queryValueOrDefault infers type from default":
+    proc t() {.async.} =
+      let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
+      let val = await pool.queryValueOrDefault("SELECT 1 WHERE false", default = -1'i32)
+      doAssert val == -1'i32
+      let val2 = await pool.queryValueOrDefault("SELECT 7", default = 0'i32)
+      doAssert val2 == 7'i32
+      await pool.close()
+
+    waitFor t()
+
   test "pool queryValueOpt":
     proc t() {.async.} =
       let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))