I’m trying to subtract a scanner input from a table value. Here’s a screenshot of my table:
Here’s what my code looks like:
x
String url = "jdbc:mysql://localhost:3306/Project";
String username = "x";
String password = "y";
try {
Scanner scanner = new Scanner(System.in);
System.out.println("What would you like to buy?");
int purchase_id = scanner.nextInt();
System.out.println("How many would you like to purchase?");
int quantity = scanner.nextInt();
Connection conn = DriverManager.getConnection(url, username, password);
Statement myStmt = conn.createStatement();
String sql = "update seattleBranch set inventory = " + quantity + "where item_id = 001";
myStmt = conn.prepareStatement(sql);
((PreparedStatement) myStmt).executeUpdate();
}
catch (SQLException e) {
e.printStackTrace();
}
}
The output of my code is:
java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'item_id = 001' at line 1
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1347)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025)
at branchComms.main(branchComms.java:27)
Here’s what I want my table to look like after subtracting 100 (my scanner input quantity):
I’m unsure as to why subtracting my scanner variable (quantity) doesn’t work, and I would appreciate any corrections to my code.
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Answer
You are missing a space in the query before the where
part, it should be like:
String sql = "update seattleBranch set inventory = " + quantity + " where item_id = 001";