You can use the match all query feature to match all rows in a table to query the total number of rows in the table or return multiple random rows.
Prerequisites
An OTSClient instance is initialized. For more information, see Initialize an OTSClient instance.
A data table is created and data is written to the data table. For more information, see Create data tables and Write data.
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. |
offset | The position from which the current query starts. |
limit | The maximum number of rows that you want the current query to return. To query only the number of rows that meet the query conditions without specific data, set the limit parameter to 0. |
query | The type of the query. To use match all query, set this parameter to TableStore.QueryType.MATCH_ALL_QUERY. |
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. |
columnToGet | Specifies whether to return all columns of each row that meets the query conditions. You can configure returnType and returnNames for this parameter.
|
Examples
The following sample code provides an example on how to use match all query 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.
*/
client.search({
tableName: TABLE_NAME,
indexName: INDEX_NAME,
searchQuery: {
offset: 0,
limit: 10, // To query only the number of rows that meet the query conditions without specific data, set the limit parameter to 0.
query: {
queryType: TableStore.QueryType.MATCH_ALL_QUERY
},
getTotalCount: true // Specify whether to return the total number of rows that meet the query conditions. Default value: false.
},
columnToGet: { // Specify the columns that you want to return. You can set this parameter to RETURN_SPECIFIED to return the specified columns, RETURN_ALL to return all columns, RETURN_ALL_FROM_INDEX to return all columns in the search index, or RETURN_NONE to return only the primary key columns.
returnType: TableStore.ColumnReturnType.RETURN_SPECIFIED,
returnNames: ["Col_1", "Col_2", "Col_3"]
}
}, function (err, data) {
if (err) {
console.log('error:', err);
return;
}
console.log('success:', JSON.stringify(data, null, 2));
});FAQ
References
The following query types are supported by search indexes: term query, terms query, match all query, match query, match phrase query, prefix query, range query, wildcard query, Boolean query, geo query, nested query, vector query, and exists query. You can select a query type to query data based on your business requirements.
If you want to sort or paginate the rows that meet the query conditions, you can use the sorting and paging feature. For more information, see Sorting and paging.
If you want to collapse the result set based on a specific column, you can use the collapse (distinct) feature. 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, such as obtaining the extreme values, sum, and total number of rows, you can perform aggregation operations or execute SQL statements. For more information, see Aggregation and SQL query.
If you want to quickly 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.