executeSql("SHOW MODULES").print(); // 结果啥 Moudle 都没有了 3.18.SET、RESET 子句 ⭐ 应用场景:SET 子句可以用于修改一些 Flink SQL 的环境配置,RESET 子句是可以将所有的环境配置恢复成默认配置,但只能在 SQL CLI 中进行使用,主要是为了让用户更纯粹的使用 SQL 而不必使用
表示先走二级索引,再走一级索引找到数据 finds relevant records based on an Index. Index Scans perform 2 read operations: one to read the index and another to read the actual value from the table. 2、顺序扫描 - Seq Scan Node finds relevant records by sequentially scanning the input record set....
签到小萌 +---+1row in set (0.00sec) extra字段详细解释说明: 14楼2022-07-29 16:35 回复 签到小萌 const row not found For a query such as SELECT … FROM tbl_name, the table was empty.(类似于select …. from tbl_name,而表记录为空) 15楼2022-07-29 16:35 回复 扫二维码下载贴吧...
SQL 语句 通用语法 通用表表达式 ALTER DATABASE ALTER OUTLINE ALTER SEQUENCE MERGE ALTER TABLE ALTER TABLEGROUP ALTER USER ALTER VIEW ANALYZE CREATE DATABASE CREATE INDEX CREATE OUTLINE DROP RESTORE POINT CREATE SEQUENCE CREATE TABLE CREATE TABLEGROUP CREATE USER CREATE VIEW DEALLOCATE PREPARE DELETE DESC...
使用EXPLAIN PLAN收集SQL语句的执行计划,通常包括以下步骤: 导入TPC-H样例数据。具体步骤参见导入样例数据。 执行EXPLAIN PLAN。 说明: 执行EXPLAIN PLAN后会将计划信息自动存储于PLAN_TABLE中,不支持对PLAN_TABLE进行INSERT、UPDATE、ANALYZE等操作。 PLAN_TABLE详细介绍见视图PLAN_TABLE。 explain plan set statement_...
Index range scan is a method for accessing a range values of a particular column. AT LEAST the leading column of the index must be supplied to access data via the index. Can be used for range operations (e.g. > < <> >= <= between) . ...
<dsql_operations> 总结和包含了查询步骤,以及查询的成本信息。 还包含所有 <dsql_operation> 块。 此标记包含整个查询的计数信息:<dsql_operations total_cost=total_cost total_number_operations=total_number_operations>total_cost 是要运行的查询的总预计时间(以毫秒为单位) 。total_number_operations 是查询...
SET EXPLAIN FILE TO '/tmp/explain.out' SELECT * FROM customer, orders WHERE customer.customer_num = orders.customer_num AND customer.lname = "Higgins"; 1. 2. 3. 4. 5. 如果用户不再希望了解下述 SQL 语句的查询计划,我们可以执行:
SQL performed on behalf of your SQL. So, if you had to parse the query, for example, you might have had to run some other queries to get data dictionary information. These would be recursive calls. Space management, security checks, calling PL/SQL from SQL—all incur recursive SQL calls...
public class Explain_Test{public static void main(String[]args)throws Exception{FlinkEnv flinkEnv=FlinkEnvUtils.getStreamTableEnv(args);flinkEnv.env().setParallelism(1);String sql="CREATE TABLE source_table (\n"+" user_id BIGINT COMMENT '用户 id',\n"+" name STRING COMMENT '用户姓名',\n...