目前看好像不行，cte 部分是要独立运行出来的。
mysql> explain with b as (select id,sum(k) as num from sbtest1 group by id), a as (select * from sbtest2) select a.id ,b.num from a,b where a.id=b.id;
+--------------------------------+-------------+-----------+-----------------------------+---------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+--------------------------------+-------------+-----------+-----------------------------+---------------------------------------------------------------------------+
| HashJoin_28 | 641.82 | root | | inner join, equal:[eq(sbtest.sbtest2.id, sbtest.sbtest1.id)] |
| ├─Selection_29(Build) | 640.00 | root | | not(isnull(sbtest.sbtest2.id)) |
| │ └─CTEFullScan_30 | 800.00 | root | CTE:a | data:CTE_1 |
| └─Selection_31(Probe) | 8000000.00 | root | | not(isnull(sbtest.sbtest1.id)) |
| └─CTEFullScan_32 | 10000000.00 | root | CTE:b | data:CTE_0 |
| CTE_1 | 800.00 | root | | Non-Recursive CTE |
| └─Selection_14(Seed Part) | 800.00 | root | | not(isnull(sbtest.sbtest2.id)) |
| └─TableReader_17 | 1000.00 | root | | data:TableFullScan_16 |
| └─TableFullScan_16 | 1000.00 | cop[tikv] | table:sbtest2 | keep order:false |
| CTE_0 | 10000000.00 | root | | Non-Recursive CTE |
| └─Projection_20(Seed Part) | 10000000.00 | root | | sbtest.sbtest1.id, cast(sbtest.sbtest1.k, decimal(32,0) BINARY)->Column#5 |
| └─IndexReader_24 | 10000000.00 | root | | index:IndexFullScan_23 |
| └─IndexFullScan_23 | 10000000.00 | cop[tikv] | table:sbtest1, index:k_1(k) | keep order:false |
+--------------------------------+-------------+-----------+-----------------------------+---------------------------------------------------------------------------+
13 rows in set (0.00 sec)