explain/desc [extanded/partitions] select … explain只能显示sql select部分的执行计划 标准输出为explain,加extanded/partitions时可以以扩展方式和树形方式输出执行计划信息 支持with … as select …类型的CTE(Common Table Expression)公用表表达式语法,需要集群层设置_t_gcluster_support_cte=1 说明 标准输出界面...
8、with as 临时表 - Common table expressions - CTE performs a sequential scan of Common Table Expression (CTE) query results. Note that results of a CTE are materialized (calculated and temporarily stored). 对公共表表达式(CTE)查询结果执行顺序扫描。注意,CTE的结果是具体化的(计算并临时存储)。 9...
returns a specified number of rows from a record set. 8、with as 临时表 - Common table expressions - CTE performs a sequential scan of Common Table Expression (CTE) query results. Note that results of a CTE are materialized (calculated and temporarily stored). 对公共表表达式(CTE)查询结果执行...
MySQL8.0.16 引入一个实验特性:explain format=tree ,树状的输出执行过程,以及预估成本和预估返回行数。在 MySQL 8.0.18 又引入了 EXPLAIN ANALYZE,在 format=tree 基础上,使用时,会执行 SQL ,并输出迭代器(感觉这里用“算子”更容易理解)相关的实际信息,比如执行成本、返回行数、执行时间,循环次数。 文档链接:h...
For a query that cannot be pushed down, object information cannot be collected and only such information as REMOTE_QUERY and CTE can be collected. For details, see Example 2. Example 1 You can perform the following steps to collect execution plans of SQL statements by running EXPLAIN PLAN: ...
delimiter//createfunctionfun_person_log(pidint)returnsintbegininsertintoperson_opration_log(pid,access_datetime)values(pid,now());returnpid;end//delimiter ; 正常的数据访问SQL如下,但是它并不写日志 mysql>select->id,->name->fromperson->whereid=1;+---+---+|id|name|+---+---+|1|项羽|+-...
(col_797) ) SELECT 'aaa730d1-11c8-42c2-a986-20afe1cd1eea':::UUID::UUID AS col_798 FROM defaultdb.public.tab_22@tab_22_col0_8_key AS tab_632, with_99 AS cte_ref_26, with_99 AS cte_ref_27 WHERE true ORDER BY tab_632.crdb_internal_mvcc_timestamp NULLS LAST, cte_ref_27...
I have figured it out. I should have usedUNION ALLinstead ofUNION.
objectname = rte->ctename; objecttag = "CTE Name"; break; default: break; } if (es->format == EXPLAIN_FORMAT_TEXT) { appendStringInfoString(es->str, " on"); if (namespace != NULL) appendStringInfo(es->str, " %s.%s", quote_identifier(namespace), quote_identifier(objectname))...
Recursive CTE's are a way to bring, well, recursion into a declarative language that SQL is. In fact, their existence is the crucial part for SQL being Turing complete.In SQL, you can create functions and put the values of their variables into WHERE, LIMIT and some other clauses of ...