You can use match all query to match all rows in a table to query the total number of rows in the table or return multiple random rows.
Prerequisites
- The TableStoreClient is initialized. For more information, see Initialize an OTSClient instance.
- A data table is created. Data is written to the table.
- A search index is created for the data table. For more information, see Create a search index.
Parameters
Parameter | Description |
TableName | The name of the data table. |
IndexName | The name of the search index. |
Query | The type of the query. Set the query type to MatchAllQuery. |
Limit | The maximum number of rows that you want the query to return. To query only the number of rows that meet the query conditions without returning specific data, you can set Limit to 0. |
GetTotalCount | Specifies whether to return the total number of rows that meet the query conditions. The default value of this parameter is false, which specifies that the total number of rows that meet the query conditions is not returned. If you set this parameter to true, the query performance is compromised. |
ColumnsToGet | Specifies whether to return all columns of each row that meets the query conditions. By default, the ReturnAll parameter is set to false, which specifies that not all columns are returned. If the ReturnAll parameter is set to false, you can use the Columns parameter to specify the columns that you want to return. If you do not specify the Columns parameter, only the primary key columns are returned. If you set the ReturnAll parameter to true, all columns in matching rows are returned. |
Examples
The following sample code provides an example on how to query the total number of rows in a table:
/**
* Perform a match all query to query the total number of rows in a table.
*/
func MatchAllQuery(client *tablestore.TableStoreClient, tableName string, indexName string) {
searchRequest := &tablestore.SearchRequest{}
searchRequest.SetTableName(tableName)
searchRequest.SetIndexName(indexName)
query := &search.MatchAllQuery{} // Set the query type to MatchAllQuery.
searchQuery := search.NewSearchQuery()
searchQuery.SetQuery(query)
searchQuery.SetGetTotalCount(true)
searchQuery.SetLimit(0) // Set the Limit parameter to 0, which specifies that the query does not return specific data rows.
searchRequest.SetSearchQuery(searchQuery)
searchResponse, err := client.Search(searchRequest)
if err != nil { // Check if an error occurs.
fmt.Printf("%#v", err)
return
}
fmt.Println("IsAllSuccess: ", searchResponse.IsAllSuccess)
fmt.Println("TotalCount: ", searchResponse.TotalCount) // Display the total number of rows in the table.
}FAQ
References
References
When you use a search index to query data, you can use the following query methods: term query, terms query, match all query, match query, match phrase query, prefix query, range query, wildcard query, geo query, Boolean query, KNN vector query, nested query, and exists query. You can use the query methods provided by the search index to query data from multiple dimensions based on your business requirements.
You can sort or paginate rows that meet the query conditions by using the sorting and paging features. For more information, see Sorting and paging.
You can use the collapse (distinct) feature to collapse the result set based on a specific column. This way, data of the specified type appears only once in the query results. For more information, see Collapse (distinct).
If you want to analyze data in a data table, you can use the aggregation feature of the Search operation or execute SQL statements. For example, you can obtain the minimum and maximum values, sum, and total number of rows. For more information, see Aggregation and SQL query.
If you want to obtain all rows that meet the query conditions without the need to sort the rows, you can call the ParallelScan and ComputeSplits operations to use the parallel scan feature. For more information, see Parallel scan.