Question

假设我有一个名为“points”的列，我想用点+ X的当前值更新“点”（其中X是任意数字）

例如

UPDATE tablename SET points=points+30 WHERE userID=1

我尝试了以下内容：

points = points + 30
points + = 30
points = tablename.points + 30

我一直在收到错误：

错误2601：Fusion表返回错误。（我在我的应用程序中查询融合表）响应是：400 Bad Request无效查询：'points'附近的解析错误

有没有办法选择点的当前值，然后UPDATE points = points + x？

编辑：问题与建议的问题相同，但它并没有解决我的问题。所以我该怎么做？我知道有人来这里编辑我写过的东西，所以用这个帖子做你想做的事情，因为你无论如何都会去。

Answer 1

FusionTables在其SQL中不支持数学。您需要使用查询来获取当前值，在SQL之外执行必要的数学运算，然后使用新值调用UPDATE。

示例（在Python中）：

getCurrent = "SELECT ROWID, points from <tableid> WHERE userID = 1"
resp = FusionTables.query().sqlGet(sql=getCurrent, ...).execute()
rowid = resp['rows'][0]
newPoints = str(int(resp['rows'][1]) + 30)
updatePoints = "UPDATE <tableid> SET points = " + newPoints + " WHERE ROWID = " + rowid
resp = FusionTables.query().sql(sql=updatePoints, ...).execute()

您一次只能更新一行，因此如果您要执行许多操作，可能会更简单/更便宜/更快地暂停更改，直到您有一定数量的操作，然后使用replaceRows批量更新（即下载所有数据，对各行进行必要的更改，然后重新上传）。如果您的数据集大于10 MB，则有额外的步骤，但这是可行的。

Answer 2

I had a similar issue. My code may be able to help someone facing this issue using Java.

I needed to update information in rows of a fusion table in many different ways that were unsupported by fusion tables implementation of SQL. I wrote a java program to help me do my updates. (I'm trying to clean up my data in my fusion table.) I also needed to find a nearby large city / state and update fields in rows with this information. Anyway, you can see the entire program on github.

The entire project directory is found on github here: https://github.com/gjkendall/FusionTableModifyJava

The code of interest is in FusionTableSample.java based on Google/Christian Junks example program of how to create, access and modify fusion tables in java. I'm new a java so it might not be the best code.

You will see a lot of commented code where I did different SQL searches for different things I needed to modify. These are there so I can reference them for future searches.

The program first does a SQL search for the rows I want to modify and puts those rows into an array(mylist). The project goes through the array mylist one row at a time, makes it's modifications (currently I needed to access geonames to get city and state info based on locations in my table) and then updates the row with a fusion table SQL call.

The routine that does the updates row by row is "updateRows" shown here:

private static void updateRows(String tableId) throws IOException {
    // IOException needed  ParseException
    count = 1;
    mylist.forEach((myRow) -> {
        try {
            // modify fields in table...
            //newAreaName = kt.firstpart(myRow.get(NOTES).toString()); //get Notes first sentence
            //newAreaName = newAreaName.replace("'", "''");
            //newAreaName += " X01";
            //String state = getStateFrmLoc(myRow.get(LOCATION).toString());
            //String state = "MX-BCS";
            float km;
            if ( "AK,MT,NV".contains(myRow.get(STATE).toString()) ) {
                km = 180f; // 111.85 miles
            } else {
                km = 80.5f;  // 50 miles
            }

            BigCity big = new BigCity(myRow.get(LOCATION).toString(), km);
            String cityState = big.cityName +", "+big.state;

            if (big.population < 10000f) {
                System.out.println("Skip for low population :"+myRow.get(NUMBER));
            } else {

                sqlupdate = "UPDATE " + tableId + " " +
                        "SET 'City (nearest)' = '" + cityState + "' " +
                        ",'Codes' = '" + myRow.get(CODES).toString() + ",#U1' " +
                        "WHERE ROWID = " + myRow.get(ROW_ID);
                System.out.println("[" + count + "]" + myRow.get(NUMBER) + ": " + sqlupdate);

                // do the update...
                if (!mtest) {  // if testing then don't update
                    sql_doupdate(sqlupdate);
                }
                count++;
                if ((count % 30) == 0) {
                    System.out.println("waiting 60 seconds");
                    TimeUnit.SECONDS.sleep(60); //Fusion Tables allows 30 updates then must wait 1 minute.
                }
            }
            } catch(Exception e){
                System.out.println(e.getMessage());
        }

    });

}

Answer 3

如果您使用的是MySQL，则必须使用以下命令禁用安全更新，SET SQL_SAFE_UPDATES = 0;

您可以使用CONCAT（）函数，这里是MySQL示例：

SELECT示例：

SELECT point, CONCAT(point, ' ', id)
FROM points_table;

更新示例：

UPDATE points_table 
SET point = CONCAT(point, ' ', id);

参考：MySQL error code: 1175 during UPDATE

FusionTables SQL：更改列的值

3 个答案: