[Feature](struct-type) Add implicitly cast for struct-type

fe/fe-common/src/main/java/org/apache/doris/catalog/StructField.java

@@ -123,8 +123,14 @@ public String prettyPrint(int lpad) {
     }
 
     public static boolean canCastTo(StructField field, StructField targetField) {
-        // TODO(xy): support cast field
-        return false;
+        // not support cast not null to nullable
+        if (targetField.containsNull != field.containsNull) {
+            return false;
+        }
+        if (targetField.type.isStringType() && field.type.isStringType()) {
+            return true;
+        }
+        return Type.canCastTo(field.type, targetField.type);
     }
 
     public boolean matchesField(StructField f) {

fe/fe-common/src/main/java/org/apache/doris/catalog/StructType.java

@@ -85,8 +85,15 @@ protected String prettyPrint(int lpad) {
     }
 
     public static boolean canCastTo(StructType type, StructType targetType) {
-        // TODO(xy) : support cast struct type
-        return false;
+        if (type.fields.size() != targetType.fields.size()) {
+            return false;
+        }
+        for (int i = 0; i < type.fields.size(); i++) {
+            if (!StructField.canCastTo(type.fields.get(i), targetType.fields.get(i))) {
+                return false;
+            }
+        }
+        return true;
     }
 
     @Override

regression-test/data/query_p0/show/test_struct_show_create.out

@@ -0,0 +1,4 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !select --
+test_struct_show_create	CREATE TABLE `test_struct_show_create` (\n  `k1` int(11) NULL,\n  `k2` STRUCT<f1:smallint(6)> NOT NULL,\n  `k3` STRUCT<f1:smallint(6),f2:int(11)> NOT NULL,\n  `k4` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20)> NOT NULL,\n  `k5` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1)> NOT NULL,\n  `k6` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20)> NULL,\n  `k7` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20),f6:date> NOT NULL,\n  `k8` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20),f6:date,f7:datetime> NOT NULL,\n  `k9` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20),f6:date,f7:datetime,f8:float> NOT NULL,\n  `k10` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20),f6:date,f7:datetime,f8:float,f9:double> NOT NULL,\n  `k11` STRUCT<f1:smallint(6),f2:int(11),f3:bigint(20),f4:char(1),f5:varchar(20),f6:date,f7:datetime,f8:float,f9:double,f10:decimal(20, 6)> NULL\n) ENGINE=OLAP\nDUPLICATE KEY(`k1`)\nCOMMENT 'OLAP'\nDISTRIBUTED BY HASH(`k1`) BUCKETS 1\nPROPERTIES (\n"replication_allocation" = "tag.location.default: 1",\n"in_memory" = "false",\n"storage_format" = "V2",\n"light_schema_change" = "true",\n"disable_auto_compaction" = "false"\n);
+

regression-test/suites/query_p0/show/test_struct_show_create.groovy

@@ -0,0 +1,79 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+suite("test_struct_show_create", "query") {
+    // define a sql table
+    def testTable = "test_struct_show_create"
+
+    sql "ADMIN SET FRONTEND CONFIG ('enable_struct_type' = 'true')"
+
+    def create_test_table = {testTablex ->
+        def result1 = sql """
+            CREATE TABLE IF NOT EXISTS ${testTable} (
+              `k1` INT(11) NULL COMMENT "",
+              `k2` STRUCT<f1:SMALLINT> NOT NULL COMMENT "",
+              `k3` STRUCT<f1:SMALLINT, f2:INT(11)> NOT NULL COMMENT "",
+              `k4` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT> NOT NULL COMMENT "",
+              `k5` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR> NOT NULL COMMENT "",
+              `k6` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20)> NULL COMMENT "",
+              `k7` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20), f6:DATE> NOT NULL COMMENT "",
+              `k8` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20), f6:DATE, f7:DATETIME> NOT NULL COMMENT "",
+              `k9` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20), f6:DATE, f7:DATETIME, f8:FLOAT> NOT NULL COMMENT "",
+              `k10` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20), f6:DATE, f7:DATETIME, f8:FLOAT, f9:DOUBLE> NOT NULL COMMENT "",
+              `k11` STRUCT<f1:SMALLINT, f2:INT(11), f3:BIGINT, f4:CHAR, f5:VARCHAR(20), f6:DATE, f7:DATETIME, f8:FLOAT, f9:DOUBLE, f10:DECIMAL(20, 6)> NULL COMMENT ""
+            ) ENGINE=OLAP
+            DUPLICATE KEY(`k1`)
+            DISTRIBUTED BY HASH(`k1`) BUCKETS 1
+            PROPERTIES (
+            "replication_allocation" = "tag.location.default: 1",
+            "storage_format" = "V2"
+            );
+            """
+
+        // DDL/DML return 1 row and 3 column, the only value is update row count
+        assertTrue(result1.size() == 1)
+        assertTrue(result1[0].size() == 1)
+        assertTrue(result1[0][0] == 0, "Create table should update 0 rows")
+
+        // insert 1 row to check whether the table is ok
+        def result2 = sql """ INSERT INTO ${testTable} VALUES
+                            (100, 
+                             {128}, 
+                             {128, 32768},
+                             {128, 32768, 2147483648},
+                             {128, 32768, 2147483648, 'c'},
+                             {128, 32768, 2147483648, 'c', "doris"},
+                             {128, 32768, 2147483648, 'c', "doris", '2023-02-10'},
+                             {128, 32768, 2147483648, 'c', "doris", '2023-02-10', '2023-02-10 12:30:00'},
+                             {128, 32768, 2147483648, 'c', "doris", '2023-02-10', '2023-02-10 12:30:00', 0.67},
+                             {128, 32768, 2147483648, 'c', "doris", '2023-02-10', '2023-02-10 12:30:00', 0.67, 0.878787878}, 
+                             {128, 32768, 2147483648, 'c', "doris", '2023-02-10', '2023-02-10 12:30:00', 0.67, 0.878787878, 6.67})
+                            """
+        assertTrue(result2.size() == 1)
+        assertTrue(result2[0].size() == 1)
+        assertTrue(result2[0][0] == 1, "Insert should update 1 rows")
+    }
+
+    try {
+        sql "DROP TABLE IF EXISTS ${testTable}"
+        create_test_table.call(testTable)
+
+        qt_select "show create table ${testTable}"
+    } finally {
+        try_sql("DROP TABLE IF EXISTS ${testTable}")
+    }
+}