15.7.7.15 SHOW CREATE VIEW Statement

SHOW CREATE VIEW view_name

This statement shows the CREATE VIEW statement that creates the named view.

mysql> SHOW CREATE VIEW v\G
*************************** 1. row ***************************
                View: v
         Create View: CREATE ALGORITHM=UNDEFINED
                      DEFINER=`bob`@`localhost`
                      SQL SECURITY DEFINER VIEW
                      `v` AS select 1 AS `a`,2 AS `b`
character_set_client: utf8mb4
collation_connection: utf8mb4_0900_ai_ci

character_set_client is the session value of the character_set_client system variable when the view was created. collation_connection is the session value of the collation_connection system variable when the view was created.

Use of SHOW CREATE VIEW requires the SHOW VIEW privilege, and the SELECT privilege for the view in question.

View information is also available from the INFORMATION_SCHEMA VIEWS table. See Section 28.3.53, “The INFORMATION_SCHEMA VIEWS Table”.

This statement also works to show the CREATE JSON DUALITY VIEW statement required to create a JSON duality view. You can also obtain information about JSON duality views from the INFORMATION_SCHEMA tables JSON_DUALITY_VIEWS, JSON_DUALITY_VIEW_COLUMNS, JSON_DUALITY_VIEW_LINKS, and JSON_DUALITY_VIEW_TABLES. See also Section 27.7.3, “JSON Duality View Metadata”.

The following example shows the SHOW CREATE VIEW statement used to create a JSON duality view:

mysql> SHOW CREATE VIEW order_dv\G
*************************** 1. row ***************************
                View: order_dv
         Create View: CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER JSON RELATIONAL DUALITY VIEW `order_dv` 
                      AS select json_duality_object( WITH (INSERT,UPDATE,DELETE) '_id':`orders`.`order_id`,'product':`orders`.`product`,'amount':`orders`.`amount`,'customer':
                      (select json_duality_object( WITH (INSERT,UPDATE) 'customer_id':`customers`.`customer_id`,'customer_name':`customers`.`name`) 
                      from `customers` where (`customers`.`customer_id` = `orders`.`customer_id`))) AS `Name_exp_1` from `orders`
character_set_client: utf8mb4
collation_connection: utf8mb4_0900_ai_ci
1 row in set (0.002 sec)

MySQL lets you use different sql_mode settings to tell the server the type of SQL syntax to support. For example, you might use the ANSI SQL mode to ensure MySQL correctly interprets the standard SQL concatenation operator, the double bar (||), in your queries. If you then create a view that concatenates items, you might worry that changing the sql_mode setting to a value different from ANSI could cause the view to become invalid. But this is not the case. No matter how you write out a view definition, MySQL always stores it the same way, in a canonical form. Here is an example that shows how the server changes a double bar concatenation operator to a CONCAT() function:

mysql> SET sql_mode = 'ANSI';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE VIEW test.v AS SELECT 'a' || 'b' as col1;
Query OK, 0 rows affected (0.01 sec)

mysql> SHOW CREATE VIEW test.v\G
*************************** 1. row ***************************
                View: v
         Create View: CREATE VIEW "v" AS select concat('a','b') AS "col1"
...
1 row in set (0.00 sec)

The advantage of storing a view definition in canonical form is that changes made later to the value of sql_mode do not affect the results from the view. However an additional consequence is that comments prior to SELECT are stripped from the definition by the server.