我有两个表，第一个表包含所有的记录，第二个表包含很少的记录，我试图把左连接得到第一个表的所有记录和第二个表中匹配的记录的数据列。

表A

id_step|id_workflow|id_action|
-------+-----------+---------+
      1|          1|       11|
      6|          1|       11|
      7|          1|       11|
      8|          1|       12|
      9|          1|       12|
     10|          1|       12|

表B

id_step|id_client|id_process|id_workflow|is_approved|action_by|action_date|
-------+---------+----------+-----------+-----------+---------+-----------+
      1|    10680|        10|          1|true       |         |           |

我希望获得以下结果预期输出

id_step|id_client|id_workflow|id_action|is_approved|action_by|action_date|
-------+---------+---------- +---------+-----------+---------+-----------+
      1|    10680|          1|       11|true       |         |           |
      6|    10680|          1|       11|pending    |         |           |
      7|    10680|          1|       11|pending    |         |           |
      8|    10680|          1|       11|pending    |         |           |
      9|    10680|          1|       11|pending    |         |           |
     10|    10680|          1|       11|pending    |         |           |

我试过查询

select 
x.id_step,
y.id_client,
x.id_workflow,
x.id_action, 
(case when y.is_approved is null then 'pending' else y.is_approved::text end ) as is_approved,
y.action_date,
y.action_by 
from nw_adsys_wfx_config as x 
left join nw_adsys_cli_wfx_process as y 
on x.id_step = y.id_step 
where x.id_workflow = 1
and y.id_process = 10

但我得到这个输出

id_step|id_client|id_workflow|id_action|is_approved|action_date|action_by|
-------+---------+-----------+---------+-----------+-----------+---------+
      1|    10680|          1|       11|true       |           |         |