MySQL - EXECUTE Statement

A prepared statement in MySQL represents a precompiled statement. A statement is compiled and stored in a prepared statement and you can later execute this multiple times. Instead of values we pass place holders to this statement.

If you want to execute several identical queries (that differ by values only). You can use prepared statements. You can execute these statements in client libraries as well as in SQL scripts.

A SQL prepared statement is based on three statements namely −

  • PREPARE
  • EXECUTE
  • DEALLOCATE PREPARE

MySQL EXECUTE Statement

The EXECUTE statement/command is used to execute the prepared statement.

Syntax

Following is the syntax of the EXECUTE statement −

EXECUTE stmt_name [USING @var_name [, @var_name] ...]

Where stmt_name is the name of the prepared statement to be executed.

Example

Suppose we have created a table named Employee in the database using the CREATE statement and inserted three records in it as shown below −

CREATE TABLE Employee(
   Name VARCHAR(255), 
   Salary INT, 
   Location VARCHAR(255)
);

You can prepare an INSERT statement with place holders instead of values as −

PREPARE prepared_stmt FROM 'INSERT INTO EMPLOYE VALUES (?, ?, ?)';
Statement prepared

Once you prepare the statement you need to set values for the place holders as follows −

SET @name = 'Raghu';

SET @sal = 9878;

SET @loc = 'Delhi';

Following query executes the above created prepared statement −

EXECUTE prepared_stmt USING @name, @sal, @loc;

Verification

After executing the prepared statement if you verify the contents of the employee table you can observe the newly inserted row −

SELECT * FROM EMPLOYEE;

Output

Following is the output of the above program −

Name Salary Location
Amit 6554 Hyderabad
Sumith 5981 Vishakhapatnam
Sudha 7887 Vijayawada
Raghu 9878 Delhi

Example

We can also execute the prepared statement omitting the variables if not required. −

--Preparing the statement
PREPARE prepared_stmt FROM 'SELECT * FROM EMPLOYE';
Statement prepared
--Executing the statement
EXECUTE prepared_stmt;

Output

The above mysql query generates the folllowing output −

Name Salary Location
Amit 6554 Hyderabad
Sumith 5981 Vishakhapatnam
Sudha 7887 Vijayawada
Raghu 9878 Delhi

Example

Assume we have created another table and populated it using the following queries −

Create table Student(Name Varchar(35), age INT, Score INT);
INSERT INTO student values ('Jeevan', 22, 8);
INSERT INTO student values ('Raghav', 26, –3);
INSERT INTO student values ('Khaleel', 21, –9);
INSERT INTO student values ('Deva', 30, 9);

You can choose the table to execute a query dynamically using this statement as shown below −

--Setting the table name dynamically
SET @table = 'Student';
SET @statement = CONCAT('SELECT * FROM ', @table);
--Preparing the statement
PREPARE prepared_stmt FROM @statement;
Statement prepared
--Executing the statement

Output

The above query produces the output shown below −

Name age Score
Jeevan 22 8
Raghav 26 -3
Khaleel 21 -9
Deva 30 9
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