fix(driver): add test for format_null_as_str

cli/src/display.rs

@@ -152,21 +152,18 @@ impl<'a> FormatDisplay<'a> {
                 );
             }
             ExpandMode::Auto => {
-                if rows.len() > 1 {
-                    println!(
-                        "{}",
-                        create_table(
-                            schema,
-                            &rows,
-                            self.replace_newline,
-                            self.settings.max_display_rows,
-                            self.settings.max_width,
-                            self.settings.max_col_width
-                        )?
-                    );
-                } else {
-                    print_expanded(schema, &rows)?;
-                }
+                // FIXME: depends on terminal size
+                println!(
+                    "{}",
+                    create_table(
+                        schema,
+                        &rows,
+                        self.replace_newline,
+                        self.settings.max_display_rows,
+                        self.settings.max_width,
+                        self.settings.max_col_width
+                    )?
+                );
             }
         }
 

cli/test.sh

@@ -32,7 +32,7 @@ case $TEST_HANDLER in
 	;;
 "http")
 	echo "==> Testing REST API handler"
-	export BENDSQL_DSN="databend+http://${DATABEND_USER}:${DATABEND_PASSWORD}@${DATABEND_HOST}:8000/?sslmode=disable&presign=on&format_null_as_str=0"
+	export BENDSQL_DSN="databend+http://${DATABEND_USER}:${DATABEND_PASSWORD}@${DATABEND_HOST}:8000/?sslmode=disable&presign=on"
 	;;
 *)
 	echo "Usage: $0 [flight|http]"

driver/tests/driver/select_simple.rs

@@ -28,12 +28,55 @@ async fn prepare() -> Box<dyn Connection> {
 
 #[tokio::test]
 async fn select_null() {
-    let conn = prepare().await;
-    let row = conn.query_row("select null").await.unwrap();
-    assert!(row.is_some());
-    let row = row.unwrap();
-    let (val,): (Option<u8>,) = row.try_into().unwrap();
-    assert_eq!(val, None);
+    {
+        let conn = prepare().await;
+        conn.exec("DROP TABLE IF EXISTS select_null").await.unwrap();
+        conn.exec(
+            "CREATE TABLE `select_null` (
+            a String,
+            b UInt64,
+            c String
+        );",
+        )
+        .await
+        .unwrap();
+        conn.exec("INSERT INTO `select_null` (a) VALUES ('NULL')")
+            .await
+            .unwrap();
+    }
+    {
+        let dsn = option_env!("TEST_DATABEND_DSN").unwrap_or(DEFAULT_DSN);
+        // ignore null to str test for flightsql
+        if !dsn.starts_with("databend+flight://") {
+            let client = Client::new(format!("{dsn}&format_null_as_str=1"));
+            let conn = client.get_conn().await.unwrap();
+            let row = conn.query_row("select * from select_null").await.unwrap();
+            assert!(row.is_some());
+            let row = row.unwrap();
+            let (val1, val2, val3): (Option<String>, Option<u64>, Option<String>) =
+                row.try_into().unwrap();
+            assert_eq!(val1, Some("NULL".to_string()));
+            assert_eq!(val2, None);
+            assert_eq!(val3, Some("NULL".to_string()));
+        }
+    }
+    {
+        let dsn = option_env!("TEST_DATABEND_DSN").unwrap_or(DEFAULT_DSN);
+        let client = Client::new(format!("{dsn}&format_null_as_str=0"));
+        let conn = client.get_conn().await.unwrap();
+        let row = conn.query_row("select * from select_null").await.unwrap();
+        assert!(row.is_some());
+        let row = row.unwrap();
+        let (val1, val2, val3): (Option<String>, Option<u64>, Option<String>) =
+            row.try_into().unwrap();
+        assert_eq!(val1, Some("NULL".to_string()));
+        assert_eq!(val2, None);
+        assert_eq!(val3, None);
+    }
+    {
+        let conn = prepare().await;
+        conn.exec("DROP TABLE IF EXISTS select_null").await.unwrap();
+    }
 }
 
 #[tokio::test]

sql/src/value.rs

@@ -230,13 +230,18 @@ impl TryFrom<(&DataType, &str)> for Value {
                 let decoder = ValueDecoder {};
                 decoder.read_field(t, &mut reader)
             }
-            DataType::Nullable(inner) => {
-                if v == NULL_VALUE {
-                    Ok(Self::Null)
-                } else {
-                    Self::try_from((inner.as_ref(), v))
+            DataType::Nullable(inner) => match inner.as_ref() {
+                DataType::String => Ok(Self::String(v.to_string())),
+                _ => {
+                    // not string type, try to check if it is NULL
+                    // for compatible with old version server
+                    if v == NULL_VALUE {
+                        Ok(Self::Null)
+                    } else {
+                        Self::try_from((inner.as_ref(), v))
+                    }
                 }
-            }
+            },
         }
     }
 }

tests/Makefile

@@ -15,7 +15,7 @@ test-core: up
 
 test-driver: up
 	cargo test --test driver
-	TEST_DATABEND_DSN=databend+flight://root:@localhost:8900/default?sslmode=disable&format_null_as_str=0 cargo test --features flight-sql --test driver
+	TEST_DATABEND_DSN=databend+flight://root:@localhost:8900/default?sslmode=disable cargo test --features flight-sql --test driver
 
 test-bendsql: up
 	cd .. && ./cli/test.sh http