Merge pull request #4242 from szarnyasg/landing-page-queries

Rework queries on the landing page

_includes/landing-page/java/appender.java

@@ -1,14 +1,14 @@
-// Using the appender for bulk inserts
-DuckDBConnection conn = (DuckDBConnection) DriverManager.getConnection("jdbc:duckdb:");
-Statement stmt = conn.createStatement();
-stmt.execute("CREATE TABLE person (first_name VARCHAR, last_name VARCHAR, age INT)");
+// Perform bulk inserts using the Appender API
+DuckDBConnection conn = (DuckDBConnection)
+    DriverManager.getConnection("jdbc:duckdb:");
+Statement st = conn.createStatement();
+st.execute("CREATE TABLE person (name VARCHAR, age INT)");
 
-try (var appender = conn.createAppender(
-        DuckDBConnection.DEFAULT_SCHEMA, "tbl"
-    )) {
-    appender.beginRow();
-    appender.append("John");
-    appender.append("Smith");
-    appender.append(42);
-    appender.endRow();
-}
+var appender = conn.createAppender(
+    DuckDBConnection.DEFAULT_SCHEMA, "person");
+
+appender.beginRow();
+appender.append("MC Ducky");
+appender.append(49);
+appender.endRow();
+appender.close();

_includes/landing-page/java/sql-query.java

@@ -1,14 +1,11 @@
 // Get a list of train stations by traffic
 Connection conn =
     DriverManager.getConnection("jdbc:duckdb:");
-Statement stmt = conn.createStatement();
-ResultSet rs = stmt.executeQuery(
-    "SELECT station_name, count(*) AS num_services\n" + 
-    "FROM train_services\n" + 
-    "GROUP BY ALL\n" + 
+Statement st = conn.createStatement();
+ResultSet rs = st.executeQuery(
+    "SELECT station_name, count(*) AS num_services\n" +
+    "FROM train_services\n" +
+    "GROUP BY ALL\n" +
     "ORDER BY num_services DESC;");
-
-while (rs.next()) {
-    System.out.println(rs.getString(1));
-    System.out.println(rs.getInt(2));
-}
+
+System.out.println(rs.next());

_includes/landing-page/sql/aggregation-full.sql

@@ -3,7 +3,9 @@ CREATE TABLE train_services AS
     FROM 's3://duckdb-blobs/train_services.parquet';
 
 -- Get the top-3 busiest train stations
-SELECT station_name, count(*) AS num_services
+SELECT
+    station_name,
+    count(*) AS num_services
 FROM train_services
 GROUP BY ALL
 ORDER BY num_services DESC

_includes/landing-page/sql/aggregation.sql

@@ -1,5 +1,7 @@
 -- Get the top-3 busiest train stations
-SELECT station_name, count(*) AS num_services
+SELECT
+    station_name,
+    count(*) AS num_services
 FROM train_services
 GROUP BY ALL
 ORDER BY num_services DESC

_includes/landing-page/sql/csv-loader.sql

@@ -1,3 +1,4 @@
--- Load CSV file, auto-detecting column name and types
+-- Load CSV file to a table. DuckDB auto-detects
+-- the CSV's format, column name and types
 CREATE TABLE stations AS
     FROM 's3://duckdb-blobs/stations.csv';

_includes/landing-page/sql/s3-parquet.sql

@@ -1,5 +1,7 @@
 -- Directly query Parquet file in S3
-SELECT station_name, count(*) AS num_services
+SELECT
+    station,
+    count(*) AS num_services
 FROM 's3://duckdb-blobs/train_services.parquet'
 GROUP BY ALL
 ORDER BY num_services DESC