Tablestore:Prefix query

1. Go to the Indexes tab.

   1. Log on to the Tablestore console.

   2. In the top navigation bar, select a resource group and a region.

   3. On the Overview page, click the name of the instance that you want to manage or click Manage Instance in the Actions column of the instance.

   4. On the Tables tab of the Instance Details tab, click the name of the data table or click Indexes in the Actions column of the data table.

2. On the Indexes tab, find the search index that you want to use to query data and click Manage Data in the Actions column.

3. In the Search dialog box, specify query conditions.

   1. By default, the system returns all attribute columns. To return specific attribute columns, turn off All Columns and specify the attribute columns that you want to return. Separate multiple attribute columns with commas (,).

      Note

      By default, the system returns all primary key columns of the data table.

   2. Select the And, Or, or Not logical operator based on your business requirements.

      If you select the And logical operator, data that meets the query conditions is returned. If you select the Or operator and specify a single query condition, data that meets the query condition is returned. If you select the Or logical operator and specify multiple query conditions, data that meets one of the query conditions is returned. If you select the Not logical operator, data that does not meet the query conditions is returned.

   3. Select a field and click Add.

   4. Set the Query Type parameter to PrefixQuery(PrefixQuery) and enter the value that you want to query.

   5. By default, the sorting feature is disabled. If you want to sort the query results based on specific fields, turn on Sort and specify the fields based on which you want to sort the query results and the sorting order.

   6. By default, the aggregation feature is disabled. If you want to collect statistics on a specific field, turn on Collect Statistics, specify the field based on which you want to collect statistics, and then configure the information that is required to collect statistics.

4. Click OK.

   Data that meets the query conditions is displayed in the specified order on the Indexes tab.

You can use the Tablestore CLI to run the search command to query data by using search indexes. For more information, see Search index.

1. Run the search command to use the search_index search index to query data and return all indexed columns of each row that meets the query conditions.

   search -n search_index --return_all_indexed

2. Enter the query conditions as prompted by the system:

   {
       "Offset": -1,
       "Limit": 10,
       "Collapse": null,
       "Sort": null,
       "GetTotalCount": true,
       "Token": null,
       "Query": {
           "Name": "PrefixQuery",
           "Query": {
               "FieldName": "col_keyword",
               "Prefix": "hangzhou"
           }
       }
   }

You can perform a prefix query by using the following Tablestore SDKs: Tablestore SDK for Java, Tablestore SDK for Go, Tablestore SDK for Python, Tablestore SDK for Node.js, Tablestore SDK for .NET, and Tablestore SDK for PHP. In this example, Tablestore SDK for Java is used.

The following sample code provides an example on how to query the rows in which the value of the Col_Keyword column contains the prefix "hangzhou" in a table:

/**
 * Search the table for rows in which the value of Col_Keyword contains the prefix "hangzhou". 
 * @param client
 */
private static void prefixQuery(SyncClient client) {
    SearchQuery searchQuery = new SearchQuery();
    PrefixQuery prefixQuery = new PrefixQuery(); // Set the query type to PrefixQuery. 
    searchQuery.setGetTotalCount(true);
    prefixQuery.setFieldName("Col_Keyword");
    prefixQuery.setPrefix("hangzhou");
    searchQuery.setQuery(prefixQuery);
    //searchQuery.setGetTotalCount(true); // Specify that the total number of matched rows is returned. 

    SearchRequest searchRequest = new SearchRequest("<TABLE_NAME>", "<SEARCH_INDEX_NAME>", searchQuery);
    // You can configure the columnsToGet parameter to specify the columns to return or specify that all columns are returned. If you do not configure this parameter, only the primary key columns are returned. 
    //SearchRequest.ColumnsToGet columnsToGet = new SearchRequest.ColumnsToGet();
    //columnsToGet.setReturnAll(true); // Specify that all columns are returned. 
    //columnsToGet.setColumns(Arrays.asList("ColName1","ColName2")); // Specify the columns that you want to return. 
    //searchRequest.setColumnsToGet(columnsToGet);

    SearchResponse resp = client.search(searchRequest);
    //System.out.println("TotalCount: " + resp.getTotalCount()); // Specify that the total number of matched rows instead of the number of returned rows is displayed. 
    System.out.println("Row: " + resp.getRows());
}