pingcap · yikeke · Jun 19, 2020 · Jun 19, 2020
diff --git a/sql-statements/sql-statement-add-column.md b/sql-statements/sql-statement-add-column.md
@@ -19,10 +19,6 @@ The `ALTER TABLE.. ADD COLUMN` statement adds a column to an existing table. Thi
 
 ![AlterTableSpec](/media/sqlgram/AlterTableSpec.png)
 
-**ColumnKeywordOpt:**
-
-![ColumnKeywordOpt](/media/sqlgram/ColumnKeywordOpt.png)
-
 **ColumnDef:**
 
 ![ColumnDef](/media/sqlgram/ColumnDef.png)
@@ -73,9 +69,10 @@ mysql> SELECT * FROM t1;
 
 ## MySQL compatibility
 
-* Adding multiple columns at the same time is currently not supported.
+* Adding multiple columns at the same time in a statement is currently not supported.
 * Adding a new column and setting it to the `PRIMARY KEY` is not supported.
 * Adding a new column and setting it to `AUTO_INCREMENT` is not supported.
+* There are limitations on adding generated columns, refer to: [generated column limitations](/generated-columns.md#limitations).
 
 ## See also
 

diff --git a/sql-statements/sql-statement-add-index.md b/sql-statements/sql-statement-add-index.md
@@ -19,17 +19,53 @@ The `ALTER TABLE.. ADD INDEX` statement adds an index to an existing table. This
 
 ![AlterTableSpec](/media/sqlgram/AlterTableSpec.png)
 
-**ColumnKeywordOpt:**
+**Constraint:**
 
-![ColumnKeywordOpt](/media/sqlgram/ColumnKeywordOpt.png)
+![Constraint](/media/sqlgram/Constraint.png)
 
-**ColumnDef:**
+**ConstraintKeywordOpt:**
 
-![ColumnDef](/media/sqlgram/ColumnDef.png)
+![ConstraintKeywordOpt](/media/sqlgram/ConstraintKeywordOpt.png)
 
-**ColumnPosition:**
+**ConstraintElem:**
 
-![ColumnPosition](/media/sqlgram/ColumnPosition.png)
+![ConstraintElem](/media/sqlgram/ConstraintElem.png)
+
+**IndexNameAndTypeOpt:**
+
+![IndexNameAndTypeOpt](/media/sqlgram/IndexNameAndTypeOpt.png)
+
+**IndexPartSpecificationList:**
+
+![IndexPartSpecificationList](/media/sqlgram/IndexPartSpecificationList.png)
+
+**IndexPartSpecification:**
+
+![IndexPartSpecification](/media/sqlgram/IndexPartSpecification.png)
+
+**IndexOptionList:**
+
+![IndexOptionList](/media/sqlgram/IndexOptionList.png)
+
+**IndexOption:**
+
+![IndexOption](/media/sqlgram/IndexOption.png)
+
+**KeyOrIndex:**
+
+![KeyOrIndex](/media/sqlgram/KeyOrIndex.png)
+
+**IndexKeyTypeOpt:**
+
+![IndexKeyTypeOpt](/media/sqlgram/IndexKeyTypeOpt.png)
+
+**IndexInvisible:**
+
+![IndexInvisible](/media/sqlgram/IndexInvisible.png)
+
+**IndexTypeName:**
+
+![IndexTypeName](/media/sqlgram/IndexTypeName.png)
 
 ## Examples
 

diff --git a/sql-statements/sql-statement-alter-database.md b/sql-statements/sql-statement-alter-database.md
@@ -9,6 +9,16 @@ aliases: ['/docs/stable/reference/sql/statements/alter-database/']
 
 `ALTER DATABASE` is used to specify or modify the default character set and collation of the current database. `ALTER SCHEMA` has the same effect as `ALTER DATABASE`.
 
+## 语法图
+
+**AlterDatabaseStmt:**
+
+![AlterDatabaseStmt](/media/sqlgram/AlterDatabaseStmt.png)
+
+**DatabaseOption:**
+
+![DatabaseOption](/media/sqlgram/DatabaseOption.png)
+
 ## Examples
 
 ```sql

diff --git a/sql-statements/sql-statement-alter-instance.md b/sql-statements/sql-statement-alter-instance.md
@@ -19,8 +19,14 @@ When an error occurs during reloading, by default, this error message is returne
 
 ## Syntax diagram
 
+**AlterInstanceStmt:**
+
 ![AlterInstanceStmt](/media/sqlgram/AlterInstanceStmt.png)
 
+**InstanceOption:**
+
+![InstanceOption](/media/sqlgram/InstanceOption.png)
+
 ## Example
 
 {{< copyable "sql" >}}

diff --git a/sql-statements/sql-statement-alter-table.md b/sql-statements/sql-statement-alter-table.md
@@ -61,8 +61,7 @@ mysql> EXPLAIN SELECT * FROM t1 WHERE c1 = 3;
 
 ## MySQL compatibility
 
-* All of the data types except spatial types are supported.
-* `FULLTEXT`, `HASH` and `SPATIAL` indexes are not supported.
+* All of the data types except spatial types are supported. For other unsupported cases, refer to: [compatibility of DDL statements with MySQL](/mysql-compatibility.md#ddl).
 
 ## See also
 

diff --git a/sql-statements/sql-statement-alter-user.md b/sql-statements/sql-statement-alter-user.md
@@ -23,6 +23,14 @@ This statement changes an existing user inside the TiDB privilege system. In the
 
 ![UserSpec](/media/sqlgram/UserSpec.png)
 
+**Username:**
+
+![Username](/media/sqlgram/Username.png)
+
+**AuthOption:**
+
+![AuthOption](/media/sqlgram/AuthOption.png)
+
 ## Examples
 
 ```sql

diff --git a/sql-statements/sql-statement-change-column.md b/sql-statements/sql-statement-change-column.md
@@ -19,10 +19,6 @@ The `ALTER TABLE.. CHANGE COLUMN` statement changes a column on an existing tabl
 
 ![AlterTableSpec](/media/sqlgram/AlterTableSpec.png)
 
-**ColumnKeywordOpt:**
-
-![ColumnKeywordOpt](/media/sqlgram/ColumnKeywordOpt.png)
-
 **ColumnName:**
 
 ![ColumnName](/media/sqlgram/ColumnName.png)

diff --git a/sql-statements/sql-statement-create-database.md b/sql-statements/sql-statement-create-database.md
@@ -15,10 +15,6 @@ This statement creates a new database in TiDB. The MySQL terminology for 'databa
 
 ![CreateDatabaseStmt](/media/sqlgram/CreateDatabaseStmt.png)
 
-**DatabaseSym:**
-
-![DatabaseSym](/media/sqlgram/DatabaseSym.png)
-
 **IfNotExists:**
 
 ![IfNotExists](/media/sqlgram/IfNotExists.png)

diff --git a/sql-statements/sql-statement-drop-column.md b/sql-statements/sql-statement-drop-column.md
@@ -19,10 +19,6 @@ This statement drops a column from a specified table. `DROP COLUMN` is online in
 
 ![AlterTableSpec](/media/sqlgram/AlterTableSpec.png)
 
-**ColumnKeywordOpt:**
-
-![ColumnKeywordOpt](/media/sqlgram/ColumnKeywordOpt.png)
-
 **ColumnName:**
 
 ![ColumnName](/media/sqlgram/ColumnName.png)
@@ -82,6 +78,7 @@ mysql> SELECT * FROM t1;
 ## MySQL compatibility
 
 * Dropping multiple columns in the same statement is not supported.
+* Dropping primary key columns or index columns is not supported.
 
 ## See also
 

diff --git a/sql-statements/sql-statement-drop-table.md b/sql-statements/sql-statement-drop-table.md
@@ -47,6 +47,7 @@ Query OK, 0 rows affected (0.23 sec)
 ## MySQL compatibility
 
 * Dropping a table with `IF EXISTS` does not return a warning when attempting to drop a table that does not exist. [Issue #7867](https://github.com/pingcap/tidb/issues/7867)
+* Currently `RESTRICT` and `CASCADE` are only supported syntactically.
 
 ## See also