From 189d1c1adb629c8af644907abe646ef6a8ed75f0 Mon Sep 17 00:00:00 2001
From: Piotr Findeisen <piotr.findeisen@gmail.com>
Date: Mon, 8 Aug 2022 13:09:58 +0200
Subject: [PATCH] Add unsupported type conversion to varchar in ClickHouse

---
 .../java/io/trino/plugin/clickhouse/ClickHouseClient.java   | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/plugin/trino-clickhouse/src/main/java/io/trino/plugin/clickhouse/ClickHouseClient.java b/plugin/trino-clickhouse/src/main/java/io/trino/plugin/clickhouse/ClickHouseClient.java
index 2119874856a7..74f62f06d893 100644
--- a/plugin/trino-clickhouse/src/main/java/io/trino/plugin/clickhouse/ClickHouseClient.java
+++ b/plugin/trino-clickhouse/src/main/java/io/trino/plugin/clickhouse/ClickHouseClient.java
@@ -131,6 +131,8 @@
 import static io.trino.plugin.jdbc.StandardColumnMappings.varbinaryWriteFunction;
 import static io.trino.plugin.jdbc.StandardColumnMappings.varcharReadFunction;
 import static io.trino.plugin.jdbc.StandardColumnMappings.varcharWriteFunction;
+import static io.trino.plugin.jdbc.TypeHandlingJdbcSessionProperties.getUnsupportedTypeHandling;
+import static io.trino.plugin.jdbc.UnsupportedTypeHandling.CONVERT_TO_VARCHAR;
 import static io.trino.spi.StandardErrorCode.GENERIC_INTERNAL_ERROR;
 import static io.trino.spi.StandardErrorCode.INVALID_ARGUMENTS;
 import static io.trino.spi.StandardErrorCode.INVALID_TABLE_PROPERTY;
@@ -616,6 +618,10 @@ public Optional<ColumnMapping> toColumnMapping(ConnectorSession session, Connect
                 return Optional.of(timestampColumnMappingUsingSqlTimestampWithRounding(TIMESTAMP_MILLIS));
         }
 
+        if (getUnsupportedTypeHandling(session) == CONVERT_TO_VARCHAR) {
+            return mapToUnboundedVarchar(typeHandle);
+        }
+
         return Optional.empty();
     }