JSTL SQL <sql:param> Tag


The <sql:param> tag used as a nested action for <sql:query> and <sql:update> to supply a value for a value placeholder. If a null value is provided, the value is set to SQL NULL for the placeholder.


The <sql:param> tag has following attributes:

AttributeDescription RequiredDefault
valueValue of the parameter to setNoBody


To start with basic concept, let us create a simple table Employees table in TEST database and create few records in that table as follows:

Step 1:

Open a Command Prompt and change to the installation directory as follows:

C:\>cd Program Files\MySQL\bin
C:\Program Files\MySQL\bin>

Step 2:

Login to database as follows

C:\Program Files\MySQL\bin>mysql -u root -p
Enter password: ********

Step 3:

Create the table Employee in TEST database as follows:

mysql> use TEST;
mysql> create table Employees
     id int not null,
     age int not null,
     first varchar (255),
     last varchar (255)
Query OK, 0 rows affected (0.08 sec)

Create Data Records

Finally you create few records in Employee table as follows:

mysql> INSERT INTO Employees VALUES (100, 18, 'Zara', 'Ali');
Query OK, 1 row affected (0.05 sec)
mysql> INSERT INTO Employees VALUES (101, 25, 'Mahnaz', 'Fatma');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO Employees VALUES (102, 30, 'Zaid', 'Khan');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO Employees VALUES (103, 28, 'Sumit', 'Mittal');
Query OK, 1 row affected (0.00 sec)

Now let us write a JSP which will make use of <sql:update> to execute a SQL DELETE statement to delete one record with id = 103 from the table as follows:

<%@ page import="java.io.*,java.util.*,java.sql.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>

<title>JSTL sql:param Tag</title>
<sql:setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
     user="root"  password="pass123"/>

<c:set var="empId" value="103"/>

<sql:update dataSource="${snapshot}" var="count">
  DELETE FROM Employees WHERE Id = ?
  <sql:param value="${empId}" />

<sql:query dataSource="${snapshot}" var="result">
   SELECT * from Employees;
<table border="1" width="100%">
<th>Emp ID</th>
<th>First Name</th>
<th>Last Name</th>
<c:forEach var="row" items="${result.rows}">
<td><c:out value="${row.id}"/></td>
<td><c:out value="${row.first}"/></td>
<td><c:out value="${row.last}"/></td>
<td><c:out value="${row.age}"/></td>


Now try to access above JSP, which should display the following result:

Emp ID First Name Last Name Age
100 Zara Ali 18
101 Mahnaz Fatma 25
102 Zaid Khan 30

You can try <sql:param> with SQL UPDATE and SELECT statements as well in the same way as I have used it with DELETE statement.