From e19eec51f83227f34d81b06e42f0a5042dbf2915 Mon Sep 17 00:00:00 2001
From: Abby <78209557+abby-cyber@users.noreply.github.com>
Date: Thu, 23 Mar 2023 12:00:30 +0800
Subject: [PATCH 1/2] Update 3.alter-tag.md

---
 docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md b/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
index 77d766e9e34..bebd209025c 100644
--- a/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
+++ b/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
@@ -10,7 +10,7 @@
 
 - The property name must be unique in a tag. If you add a property with the same name as an existing property or a dropped property, the operation fails.
 
-- Only the length of a `FIXED_STRING` or an `INT` can be increased.
+- Only the length of a `FIXED_STRING` or an `INT` can be increased. The length of a `STRING` or an `INT` cannot be decreased.
 
 - Only the data type conversions from FIXED_STRING to STRING and from FLOAT to DOUBLE are allowed.
 
@@ -42,12 +42,12 @@ ttl_definition:
 
 ```ngql
 nebula> CREATE TAG IF NOT EXISTS t1 (p1 string, p2 int);
-nebula> ALTER TAG t1 ADD (p3 int, p4 string);
+nebula> ALTER TAG t1 ADD (p3 int32, fixed_string(10));
 nebula> ALTER TAG t1 TTL_DURATION = 2, TTL_COL = "p2";
 nebula> ALTER TAG t1 COMMENT = 'test1';
 nebula> ALTER TAG t1 ADD (p5 double NOT NULL DEFAULT 0.4 COMMENT 'p5') COMMENT='test2';
-// Change the `p3` property to INT8 
-nebula> ALTER TAG t1 CHANGE (p3 int8, p4 string);
+// Change the data type of p3 in the TAG t1 from INT32 to INT64, and that of p4 from FIXED_STRING(10) to STRING.
+nebula> ALTER TAG t1 CHANGE (p3 int64, p4 string);
 [ERROR(-1005)]: Unsupported!
 ```
 

From 8eb7363e3b7f94d0805a0624fa010192e3b00c64 Mon Sep 17 00:00:00 2001
From: Abby <78209557+abby-cyber@users.noreply.github.com>
Date: Thu, 23 Mar 2023 14:12:53 +0800
Subject: [PATCH 2/2] Update 3.alter-tag.md

---
 docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md b/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
index bebd209025c..ba5d79eec2b 100644
--- a/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
+++ b/docs-2.0/3.ngql-guide/10.tag-statements/3.alter-tag.md
@@ -10,10 +10,6 @@
 
 - The property name must be unique in a tag. If you add a property with the same name as an existing property or a dropped property, the operation fails.
 
-- Only the length of a `FIXED_STRING` or an `INT` can be increased. The length of a `STRING` or an `INT` cannot be decreased.
-
-- Only the data type conversions from FIXED_STRING to STRING and from FLOAT to DOUBLE are allowed.
-
 
 ## Syntax
 
@@ -38,6 +34,12 @@ ttl_definition:
 
 - When a property value is set to `NOT NULL` using `ADD` or `CHANGE`, a default value must be specified for the property, that is, the value of `DEFAULT` must be specified.
 
+- When using `CHANGE` to modify the data type of a property:
+  
+  - Only the length of a `FIXED_STRING` or an `INT` can be increased. The length of a `STRING` or an `INT` cannot be decreased.
+
+  - Only the data type conversions from FIXED_STRING to STRING and from FLOAT to DOUBLE are allowed.
+
 ## Examples
 
 ```ngql