MySQL查询，在where子句中使用多个具有相同名称的表字段

Question

我有一个带有多个联接的select语句，每个联接都有一个名为“ created_on”的列名，有没有一种方法可以使查询的where部分将检查所有3个表？ 这是我所做的实际查询

SELECT *
FROM household_address
JOIN catchment_area ON catchment_area.household_id = household_address.household_id
JOIN bhw ON catchment_area.bhw_id = bhw.user_username
JOIN master_list ON master_list.person_id = catchment_area.person_id
JOIN house_visits ON house_visits.household_id = household_address.household_id
WHERE catchment_area.household_id IN (
  SELECT household_address.household_id
  FROM demo.household_address
  JOIN catchment_area ON catchment_area.household_id = household_address.household_id
  JOIN previous_cases ON catchment_area.person_id = previous_cases.person_id
  JOIN active_cases ON catchment_area.person_id = active_cases.person_id
  JOIN ls_report ON ls_report.ls_household = household_address.household_name
  WHERE DATE(created_on) BETWEEN '2014-03-01' AND '2014-03-31' 
)

我正在谈论的联接是子查询中的联接。

Answer 1

首先，您应该像这样为每个表名创建一个别名，以使其更易于阅读和编写。

SELECT *
FROM household_address AS ha
JOIN catchment_area ca ON ca.household_id = ha.household_id
JOIN bhw bh ON ca.bhw_id = bh.user_username
JOIN master_list ml ON ml.person_id = ca.person_id
JOIN house_visits hv ON hv.household_id = ha.household_id
WHERE ca.household_id IN 
(
    SELECT ha1.household_id
    FROM demo.household_address AS ha1
    JOIN ca1 ON ca1.household_id = ha1.household_id
    JOIN previous_cases pc ON ca1.person_id = pc.person_id
    JOIN active_cases ac ON ca1.person_id = ac.person_id
    JOIN ls_report ls_r ON ls_r.ls_household = ha1.household_name
    WHERE DATE(ha1.created_on)  BETWEEN '2014-03-01' AND '2014-03-31' 
      AND DATE(ca1.created_on)  BETWEEN '2014-03-01' AND '2014-03-31'
      AND DATE(pc.created_on)   BETWEEN '2014-03-01' AND '2014-03-31'
      AND DATE(ac.created_on)   BETWEEN '2014-03-01' AND '2014-03-31'
      AND DATE(ls_r.created_on) BETWEEN '2014-03-01' AND '2014-03-31'
)

对于创建日期的每个条件，您必须告诉它WHERE（table_name.created_on BETWEEN .....）

对每个表都这样做，这应该工作

Answer 2

尝试将别名与其他WHERE子句一起使用。

SELECT 
    *
FROM household_address
JOIN catchment_area ON catchment_area.household_id = household_address.household_id
JOIN bhw ON catchment_area.bhw_id = bhw.user_username
JOIN master_list ON master_list.person_id = catchment_area.person_id
JOIN house_visits ON house_visits.household_id = household_address.household_id
WHERE catchment_area.household_id IN (
  SELECT household_address.household_id
  FROM demo.household_address ha
  JOIN catchment_area ca ON ca.household_id = ha.household_id
  JOIN previous_cases pc ON ca.person_id = pc.person_id
  JOIN active_cases ac ON ca.person_id = ac.person_id
  JOIN ls_report ls_r ON ls_r.ls_household = ha.household_name
  WHERE DATE(ha.created_on) BETWEEN '2014-03-01' AND '2014-03-31' 
  AND DATE(ca.created_on) BETWEEN '2014-03-01' AND '2014-03-31' 
  AND DATE(pc.created_on) BETWEEN '2014-03-01' AND '2014-03-31' 
)

我实际上不知道哪三个表具有“ created_on”字段，因此我以household_address，catchment_area和previous_cases为例。 将其更改为您实际要搜索的内容。

（也应该为所有表名加上别名）