Question

我正在尝试在出现重复键时更新一行中的列。如果列当前不等于“C”，我只想更新列。我已经查看了所有在线信息，这看起来还不错。但是，我得到的错误消息是语法附近有错误：

WHERE VALUES(cad_status_flag) <> 'C' OR VALES(cad_status_flag) IS NULL

我试过没有VALUES，即WHERE cad_status_flag＆lt;＆gt; 'C'或ad_status_flag为NULL，发生相同的错误消息。

SQL是：

String selectQry5 = ("INSERT INTO at_cub_award_date " +
            "(ca_id, ad_id, cad_task_completion_date, cad_status_flag) " +
            "VALUES (?, ?, ?, ?) " +
            //"ON DUPLICATE KEY UPDATE cad_status_flag=? WHERE VALUES(cad_status_flag) <> 'C' OR VALUES(cad_status_flag) IS NULL;");

MySQL不允许使用WHERE，因此我将其替换为IF

"ON DUPLICATE KEY UPDATE " +
    "cad_status_flag = IF(cad_status_flag <> 'C' OR cad_status_flag IS NULL, VALUES(cad_status_flag), cad_status_flag;");
//Create the at_cub_award_date order 1 row
        try {
            // Create a statement and execute the query on it               
            ps5.setString(1, caid);
            ps5.setString(2, adid);
            ps5.setString(3, awardedDate);
            ps5.setString(4, groupCompleted);
            ps5.setString(5, groupCompleted);

            ps5.executeUpdate();

            //Get foreign key from insert into at_cub_awards
            ResultSet rs = ps5.getGeneratedKeys();
            if (rs.next()) {
                ymAwards = new YMAwards(rs.getString(1), null, null, null, null);
            };

            // Clean up
            ps5.close();
            c.close();
            System.out.println("addYMAwards5 completed: ");

        } catch (SQLException se) {
            System.out.println("SQLException in addYMAwards5: " + se.toString());
        } catch (Exception e) {
            System.out.println("Errors occurred in addYMAwards5: " + e.toString());
        }

现在我在addYMAwards5中收到错误“SQLException：com.mysql.jdbc.exception.jdbc.exzception.jdbc4.MySQLSyntaxErrorException：您的SQL语法中有错误;请查看与您的MySQL服务器版本对应的手册在'第1行'附近使用正确的语法

Answer 1

我发现很难遵循你的逻辑。您似乎希望在CASE子句中使用ON DUPLICATE KEY UPDATE语句：

INSERT INTO at_cub_award_date(ca_id, ad_id, cad_task_completion_date, cad_status_flag) 
    SELECT ?, ?, ?, ?
    FROM dual
    ON DUPLICATE KEY UPDATE
        cad_status_flag = (CASE WHEN VALUES(cad_status_flag) <> 'C' OR VALUES(cad_status_flag) IS NULL
                                THEN ? ELSE cad_status_flag
                           END);

Answer 2

MySQL不允许WHERE，你必须使用IF。

String selectQry5 = ("INSERT INTO at_cub_award_date " +
            "(ca_id, ad_id, cad_task_completion_date, cad_status_flag) " +
            "VALUES (?, ?, ?, ?) " +
            "ON DUPLICATE KEY UPDATE " +
                "cad_status_flag = IF(cad_status_flag <> 'C' OR cad_status_flag IS NULL, VALUES(cad_status_flag), cad_status_flag);");

注意：VALUES（cad_status_flag）可以替换为？只要你添加ps5.setString（5，groupCompleted）;在准备好的声明中。

MySQL Prepared Statement - 使用WHERE语句

2 个答案: