MySQL - SHOW FUNCTION STATUS Statement

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MySQL SHOW FUNCTION STATUS Statement

A function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing. You can create a stored function using the CREATE FUNCTION statement.

The MySQL SHOW FUNCTION STATUS statement displays the features of the stored functions. It provides information such as −

• Name of the procedure.
• Database in which it is created.
• Type of the procedure.
• Creator of the procedure.
• Modification dates etc.…

Syntax

Following is the syntax the SHOW FUNCTION STATUS statement −

SHOW FUNCTION STATUS
   [LIKE 'pattern' | WHERE expr]

Example

Following statement displays the characteristics of stored functions −

SHOW FUNCTION STATUS\G;

Output

The above query produces the output shown below −

************** 1. row **************
                  Db: test
                Name: areaOfCircle
                Type: FUNCTION
             Definer: root@localhost
            Modified: -------------------
             Created: -------------------
       Security_type: DEFINER
             Comment:
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 2. row **************
                  Db: test
                Name: demo
                Type: FUNCTION
             Definer: root@localhost
            Modified: -------------------
             Created: -------------------
       Security_type: DEFINER
             Comment:
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 3. row **************
                  Db: test
                Name: sample
                Type: FUNCTION
             Definer: root@localhost
            Modified: -------------------
             Created: -------------------
       Security_type: DEFINER
             Comment:
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 4. row **************
                  Db: test
                Name: while_example
                Type: FUNCTION
             Definer: root@localhost
            Modified: -------------------
             Created: -------------------
       Security_type: DEFINER
             Comment:
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 5. row **************
                  Db: test
                Name: test
                Type: FUNCTION
             Definer: root@localhost
            Modified: -------------------
             Created: -------------------
       Security_type: DEFINER
             Comment:
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .

The LIKE clause

Using the LIKE clause, you can specify a pattern to retrieve information about the functions.

Example

Assume we have created a new database and created 3 functions in it using the CREATE statement as shown below −

CREATE demo;
use dem;
database changed
DELIMITER //
CREATE FUNCTION TestAdd(a INT, b INT) RETURNS INT DETERMINISTIC
   BEGIN
      DECLARE res INT;
      SET res=a+b;
      RETURN res;
   END//
   Query OK, 0 rows affected (0.29 sec)
CREATE FUNCTION TestSub (a INT, b INT) RETURNS INT DETERMINISTIC
   BEGIN
      DECLARE res INT;
      SET res=a-b;
      RETURN res;
   END//
   Query OK, 0 rows affected (0.29 sec)
CREATE FUNCTION TestMul (a INT, b INT) RETURNS INT DETERMINISTIC
   BEGIN
      DECLARE res INT;
      SET res=a*b;
      RETURN res;
   END//
   Query OK, 0 rows affected (0.29 sec)
CREATE FUNCTION TestDiv (a INT, b INT) RETURNS INT DETERMINISTIC
   BEGIN
      DECLARE res INT;
      SET res=a/b;
      RETURN res;
   END//
   Query OK, 0 rows affected (0.29 sec)
DELIMITER ;

Following query retrieves the information about the procedures whose name starts with the word "Test".

SHOW FUNCTION STATUS LIKE 'Test%'\G;

Output

Once the query is executed, it will produce the following output −

************** 1. row **************
                  Db: demo
			    Name: TestAdd
			    Type: FUNCTION
		     Definer: root@localhost
		    Modified: 2021-05-14 06:37:04
		     Created: 2021-05-14 06:37:04
       Security_type: DEFINER
		     Comment: 
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 2. row **************
                  Db: demo
			    Name: TestDiv
			    Type: FUNCTION
		     Definer: root@localhost
		    Modified: 2021-05-14 06:37:22
		     Created: 2021-05-14 06:37:22
       Security_type: DEFINER
		     Comment: 
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 3. row **************
                  Db: demo
			    Name: TestMul
			    Type: FUNCTION
		     Definer: root@localhost
		    Modified: 2021-05-14 06:37:16
		     Created: 2021-05-14 06:37:16
       Security_type: DEFINER
		     Comment: 
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci
************** 4. row **************
                  Db: demo
			    Name: TestSub
			    Type: FUNCTION
		     Definer: root@localhost
		    Modified: 2021-05-14 06:37:10
		     Created: 2021-05-14 06:37:10
       Security_type: DEFINER
		     Comment: 
character_set_client: cp850
collation_connection: cp850_general_ci
  Database Collation: utf8mb4_0900_ai_ci

The WHERE clause

You can use the WHERE clause of the SHOW PROCEDURE STATUS statements to retrieve information about the procedures which match the specified condition.

Example

Suppose we have created a table named Emp in the database using the CREATE statement as shown below −

CREATE TABLE Emp(Name VARCHAR(255), DOB DATE, Location VARCHAR(255));

Now, let's insert some records into the Emp table using the INSERT statement −

INSERT INTO Emp VALUES 
('Amit', DATE('1970-01-08'), 'Hyderabad'),
('Sumith', DATE('1990-11-02'), 'Vishakhapatnam'),
('Sudha', DATE('1980-11-06'), 'Vijayawada');

Assume we have created a getDob() function which accepts the name of the employee, retrieves and returns the value of DOB column.

DELIMITER //
CREATE FUNCTION test.getDob(emp_name VARCHAR(50))
   RETURNS DATE
   DETERMINISTIC
   BEGIN
      declare dateOfBirth DATE;
      select DOB into dateOfBirth from test.emp where Name = emp_name;
      return dateOfBirth;
   END//
DELIMITER ;

In the same way if we have created another table shown below −

CREATE TABLE student (Name VARCHAR(100), Math INT, English INT, 
Science INT, History INT);

Let us insert some records into the student table −

INSERT INTO student values
('Raman', 95, 89, 85, 81),
('Rahul' , 90, 87, 86, 81),
('Mohit', 90, 85, 86, 81),
('Saurabh', NULL, NULL, NULL, NULL );

Following function updates the above create table −

Create Function test.tbl_Update(S_name Varchar(50), M1 INT, 
M2 INT, M3 INT, M4 INT)
   RETURNS INT
   DETERMINISTIC
   BEGIN
      UPDATE student SET Math = M1, English = M2, Science = M3, 
	  History = M4 WHERE Name = S_name;
      RETURN 1;
   END //
DELIMITER ;

You can verify the list of functions in a database using the SHOW FUNCTION STATUS statement as shown below −

SHOW FUNCTION STATUS WHERE db = 'test'\G;

Output

The above query produces the following output −

************** 1. row **************
                     Db: test
				   Name: getDob
				   Type: FUNCTION
				Definer: root@localhost
			   Modified: 2021-03-21 11:21:12
				Created: 2021-03-13 14:45:36
		  Security_type: DEFINER
				Comment: This is a sample comment
   character_set_client: cp850
   collation_connection: cp850_general_ci
	 Database Collation: utf8mb4_0900_ai_ci
************** 2. row **************
                     Db: test
				   Name: tbl_Update
				   Type: FUNCTION
				Definer: root@localhost
			   Modified: 2021-03-13 22:16:05
				Created: 2021-03-13 22:16:05
		  Security_type: DEFINER
				Comment: 
   character_set_client: cp850
   collation_connection: cp850_general_ci
	 Database Collation: utf8mb4_0900_ai_ci

Following queries deletes/drops the above created functions −

DROP FUNCTION getDob;

DROP FUNCTION tbl_update;

Since we have deleted both the functions. If you verify the list of function again you will get an empty set −

SHOW FUNCTION STATUS WHERE db = 'test';
Empty set (0.00 sec)