Editing SQL in JAVA where must be boolean-CodePudding

I'm editing SQL in JAVA but keep getting ERROR

If I'm understanding it correctly, if state is OK I should get

SELECT name FROM inventura_table where state='O'

when I execute same select by script it works just fine

Connection conn = DriverManager.getConnection(url, user, password);
            String SQL = "SELECT name FROM inventura_table where ?";
            PreparedStatement pstmt = conn.prepareStatement(SQL);

            ResultSet rs;
            switch (state) {
                case "OK":
                    pstmt.setString(1, "state='O' ");
                    break;
                case "M":
                    pstmt.setString(1, "state='M' ");
                    break;
                case "V":
                    pstmt.setString(1, "state='V' ");
                    break;
                case "removed":
                    pstmt.setString(1, "out_date IS NOT NULL");
                    break;
                }

Error

ERROR: argument of WHERE must be type boolean, not type character varying

CodePudding user response：

What you are trying is not possible. You can only set values to conditions, not create new conditions.

You could do something like this:

Connection conn = DriverManager.getConnection(url, user, password);
String SQL = "SELECT name FROM inventura_table";

if (state.equals("removed")) {
  SQL  = " where out_date IS NOT NULL";
}
else {
  SQL  = " where state = ?";
}

PreparedStatement pstmt = conn.prepareStatement(SQL);

ResultSet rs;
switch (state) {
   case "OK":
      pstmt.setString(1, "O");  
      break;
   case "M":
      pstmt.setString(1, "M");
      break;
   case "V":
      pstmt.setString(1, "V");
      break;
}