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Open the README with a quick start that runs #33

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27 changes: 21 additions & 6 deletions README.md
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Expand Up @@ -9,18 +9,33 @@ streaming, forward-only result sets over ClickHouse SQL.
> public API is not frozen. See
> [What works today](#what-works-today).

## Quick start

```java
try (Connection connection = DriverManager.getConnection("jdbc:chdb::memory:");
String logs = "{\"path\":\"/\",\"status\":200}{\"path\":\"/admin\",\"status\":403}{\"path\":\"/\",\"status\":200}";

try (Connection connection = DriverManager.getConnection("jdbc:chdb:");
PreparedStatement statement = connection.prepareStatement(
"SELECT count() FROM url(?, 'JSONEachRow') WHERE status = 200")) {
statement.setString(1, "https://example.com/logs.jsonl");
try (ResultSet rs = statement.executeQuery()) {
rs.next();
System.out.println(rs.getLong(1));
"SELECT path, count() FROM format(JSONEachRow, ?) WHERE status = 200 GROUP BY path")) {
statement.setString(1, logs);
try (ResultSet results = statement.executeQuery()) {
while (results.next()) {
System.out.println(results.getString(1) + " " + results.getLong(2)); // / 2
}
}
}
```

One dependency ([Installing](#installing)) and that runs: JSON in, an aggregate out, with no
schema declared, no load step and no server — and no `Class.forName`, because the driver
registers itself and the first `getConnection` maps the engine into this JVM.

Swap `format(JSONEachRow, ?)` for `file(?, 'JSONEachRow')` or `url(?, 'JSONEachRow')` and the
rest of the query is unchanged. That is the whole of it.

[`QuickStart.java`](chdb-examples/src/main/java/org/chdb/examples/QuickStart.java) carries on
from here: the type matrix, `ResultSetMetaData`, and streaming a result larger than the heap.

## Support matrix

Every one of the four platforms builds, passes the full test suite on Java 11, 17, 21 and 25,
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