diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/MapType.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/MapType.java
index d7e11db914..2f06c1d7f7 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/MapType.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/MapType.java
@@ -104,7 +104,7 @@ public class MapType extends DataType {
 
     @Override
     public String toSql() {
-        return "MAP<" + keyType.toSql() + ", " + valueType.toSql() + ">";
+        return "MAP<" + keyType.toSql() + "," + valueType.toSql() + ">";
     }
 
     @Override
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StringType.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StringType.java
index 9e13096385..935716e42b 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StringType.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StringType.java
@@ -43,7 +43,7 @@ public class StringType extends CharacterType {
 
     @Override
     public String simpleString() {
-        return "string";
+        return "text";
     }
 
     @Override
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructField.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructField.java
index 73533fc0a5..e095f25aa6 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructField.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructField.java
@@ -19,6 +19,7 @@ package org.apache.doris.nereids.types;
 
 import org.apache.doris.nereids.util.Utils;
 
+import java.util.Locale;
 import java.util.Objects;
 
 /**
@@ -38,7 +39,7 @@ public class StructField {
      *  @param nullable Indicates if values of this field can be `null` values
      */
     public StructField(String name, DataType dataType, boolean nullable, String comment) {
-        this.name = Objects.requireNonNull(name, "name should not be null");
+        this.name = Objects.requireNonNull(name, "name should not be null").toLowerCase(Locale.ROOT);
         this.dataType = Objects.requireNonNull(dataType, "dataType should not be null");
         this.nullable = nullable;
         this.comment = Objects.requireNonNull(comment, "comment should not be null");
@@ -82,7 +83,7 @@ public class StructField {
 
     public String toSql() {
         return name + ":" + dataType.toSql()
-                + (nullable ? " " : " NOT NULL")
+                + (nullable ? "" : " NOT NULL")
                 + (comment.isEmpty() ? "" : " COMMENT " + comment);
     }
 
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructType.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructType.java
index 0e53874b2d..ef7dd06165 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructType.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/types/StructType.java
@@ -119,11 +119,11 @@ public class StructType extends DataType {
 
     @Override
     public String toSql() {
-        return "STRUCT<" + fields.stream().map(StructField::toSql).collect(Collectors.joining(", ")) + ">";
+        return "STRUCT<" + fields.stream().map(StructField::toSql).collect(Collectors.joining(",")) + ">";
     }
 
     @Override
     public String toString() {
-        return "STRUCT<" + fields.stream().map(StructField::toString).collect(Collectors.joining(", ")) + ">";
+        return "STRUCT<" + fields.stream().map(StructField::toString).collect(Collectors.joining(",")) + ">";
     }
 }
diff --git a/fe/fe-core/src/test/java/org/apache/doris/nereids/types/DataTypeTest.java b/fe/fe-core/src/test/java/org/apache/doris/nereids/types/DataTypeTest.java
index c0dfe19d04..9f19d815c8 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/nereids/types/DataTypeTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/nereids/types/DataTypeTest.java
@@ -564,7 +564,7 @@ public class DataTypeTest {
         Assertions.assertEquals("decimal", DecimalV2Type.SYSTEM_DEFAULT.simpleString());
         Assertions.assertEquals("char", new CharType(10).simpleString());
         Assertions.assertEquals("varchar", VarcharType.SYSTEM_DEFAULT.simpleString());
-        Assertions.assertEquals("string", StringType.INSTANCE.simpleString());
+        Assertions.assertEquals("text", StringType.INSTANCE.simpleString());
         Assertions.assertEquals("date", DateType.INSTANCE.simpleString());
         Assertions.assertEquals("datetime", DateTimeType.INSTANCE.simpleString());
     }
diff --git a/regression-test/suites/query_p0/show/test_nested_complex_switch.groovy b/regression-test/suites/query_p0/show/test_nested_complex_switch.groovy
index 5639d52ddb..af39d8a9c3 100644
--- a/regression-test/suites/query_p0/show/test_nested_complex_switch.groovy
+++ b/regression-test/suites/query_p0/show/test_nested_complex_switch.groovy
@@ -170,17 +170,17 @@ suite("test_nested_complex_switch", "query") {
         // struct
         test {
             sql sql_s_s
-            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported field type: STRUCT<f11:BOOLEAN> for STRUCT"
+            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported"
         }
 
         test {
             sql sql_s_a
-            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported field type: ARRAY<INT> for STRUCT"
+            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported"
         }
 
         test {
             sql sql_s_m
-            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported field type: MAP<BOOLEAN,TINYINT> for STRUCT"
+            exception "java.sql.SQLException: errCode = 2, detailMessage = Unsupported"
         }
 
     } finally {