通过作为JOIN查询一部分的ID进行筛选

Question

我正在查询包含许多联结的wthat。这回来的数据是正确的：

SELECT 
    cmb.item_id, 
    cmba.field_id, 
    cmba.attr_val, 
    cmba.upd_dtt, 
    cmba.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_member_brg_attr cmba 
    ON (cmb.item_id = cmba.item_id) where cmb.item_id=8086 
UNION 
SELECT 
    cmb.item_id, 
    ca.field_id, 
    ca.attr_val, 
    ca.upd_dtt, 
    ca.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_attr ca 
    ON (cmb.contract_item_id = ca.item_id) 
WHERE ca.field_id IN (413) and cmb.item_id=8086 
UNION 
SELECT 
    cmb.item_id, 
    91, 
    m.item_name, 
    m.upd_dtt, 
    m.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_attr ca 
    ON (cmb.contract_item_id = ca.item_id 
    AND ca.field_id = 234) 
INNER JOIN mfr m 
    ON (ca.attr_val = m.item_pk); 

我试图过滤特定ITEM_ID：

我已经尝试了WHERE子句中与各地不同的别名的地方。

我在哪里可以添加一个过滤器到这个查询，以便我只能返回此select语句中的特定item_id？

Answer 1

让你的整个查询的子查询和过滤器上：

select * from 
(SELECT 
    cmb.item_id, 
    cmba.field_id, 
    cmba.attr_val, 
    cmba.upd_dtt, 
    cmba.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_member_brg_attr cmba 
    ON (cmb.item_id = cmba.item_id) where cmb.item_id=8086 
UNION 
SELECT 
    cmb.item_id, 
    ca.field_id, 
    ca.attr_val, 
    ca.upd_dtt, 
    ca.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_attr ca 
    ON (cmb.contract_item_id = ca.item_id) 
WHERE ca.field_id IN (413) and cmb.item_id=8086 
UNION 
SELECT 
    cmb.item_id, 
    91, 
    m.item_name, 
    m.upd_dtt, 
    m.upd_usr 
FROM contract_member_brg cmb 
INNER JOIN contract_attr ca 
    ON (cmb.contract_item_id = ca.item_id 
    AND ca.field_id = 234) 
INNER JOIN mfr m 
    ON (ca.attr_val = m.item_pk) 
) a 
where item_id = 'whatevs'; 

Here is an example to demonstrate