diff --git a/.github/workflows/test-mongodb.yml b/.github/workflows/test-mongodb.yml
index 4ac6d329..e66620dd 100644
--- a/.github/workflows/test-mongodb.yml
+++ b/.github/workflows/test-mongodb.yml
@@ -11,6 +11,7 @@ jobs:
         strategy:
             matrix:
                 go-version: [1.14.x, 1.15.x]
+                platform: [ubuntu-latest, windows-latest]
         steps:
             - name: Install Go
               uses: actions/setup-go@v1
diff --git a/.github/workflows/test-mysql.yml b/.github/workflows/test-mysql.yml
index 496388b1..2613b825 100644
--- a/.github/workflows/test-mysql.yml
+++ b/.github/workflows/test-mysql.yml
@@ -21,6 +21,7 @@ jobs:
         strategy:
             matrix:
                 go-version: [1.14.x, 1.15.x]
+                platform: [ubuntu-latest, windows-latest]
         steps:
             - name: Install Go
               uses: actions/setup-go@v1
diff --git a/.github/workflows/test-redis.yml b/.github/workflows/test-redis.yml
index bfd63a34..c25fe345 100644
--- a/.github/workflows/test-redis.yml
+++ b/.github/workflows/test-redis.yml
@@ -11,6 +11,7 @@ jobs:
         strategy:
             matrix:
                 go-version: [1.14.x, 1.15.x]
+                platform: [ubuntu-latest, windows-latest]
         steps:
             - name: Install Go
               uses: actions/setup-go@v1
diff --git a/mysql/mysql.go b/mysql/mysql.go
index 7e553ab9..45ea29d1 100644
--- a/mysql/mysql.go
+++ b/mysql/mysql.go
@@ -75,7 +75,7 @@ func New(config ...Config) *Storage {
 	store := &Storage{
 		gcInterval: cfg.GCInterval,
 		db:         db,
-		sqlSelect:  fmt.Sprintf(`SELECT data, exp FROM %s WHERE id=?;`, cfg.Table),
+		sqlSelect:  fmt.Sprintf("SELECT data, exp FROM %s WHERE id=?;", cfg.Table),
 		sqlInsert:  fmt.Sprintf("INSERT OR REPLACE INTO %s (id, data, exp) VALUES (?,?,?)", cfg.Table),
 		sqlDelete:  fmt.Sprintf("DELETE FROM %s WHERE id=?", cfg.Table),
 		sqlClear:   fmt.Sprintf("DELETE FROM %s;", cfg.Table),
@@ -102,10 +102,10 @@ func (s *Storage) Get(key string) ([]byte, error) {
 	)
 
 	if err := row.Scan(&data, &exp); err != nil {
-		if err.Error() != noRows {
-			return nil, err
+		if err == sql.ErrNoRows {
+			return nil, ErrNotExist
 		}
-		return nil, nil
+		return nil, err
 	}
 
 	// If the expiration time has already passed, then return nil
diff --git a/postgres/postgres.go b/postgres/postgres.go
index 369f12b4..64b00368 100644
--- a/postgres/postgres.go
+++ b/postgres/postgres.go
@@ -99,7 +99,7 @@ func New(config ...Config) *Storage {
 		db:         db,
 		gcInterval: cfg.GCInterval,
 		sqlSelect:  fmt.Sprintf(`SELECT data, exp FROM %s WHERE key=$1;`, cfg.Table),
-		sqlInsert:  fmt.Sprintf("INSERT OR REPLACE INTO %s (key, data, exp) VALUES ($1, $2, $3)", cfg.Table),
+		sqlInsert:  fmt.Sprintf(`INSERT INTO %s (key, data, exp) VALUES ($1, $2, $3) ON DUPLICATE KEY UPDATE data="$1", exp=$3`, cfg.Table),
 		sqlDelete:  fmt.Sprintf("DELETE FROM %s WHERE key=$1", cfg.Table),
 		sqlClear:   fmt.Sprintf("DELETE FROM %s;", cfg.Table),
 		sqlGC:      fmt.Sprintf("DELETE FROM %s WHERE exp <= $1", cfg.Table),
@@ -122,10 +122,10 @@ func (s *Storage) Get(key string) ([]byte, error) {
 		exp  int64 = 0
 	)
 	if err := row.Scan(&data, &exp); err != nil {
-		if err != noRows {
-			return nil, err
+		if err == sql.ErrNoRows {
+			return nil, ErrNotExist
 		}
-		return nil, nil
+		return nil, err
 	}
 
 	// If the expiration time has already passed, then return nil