select t.*
from talk t
where t.user_id = 2
Union
select t.*
from talk t, user_contact c
where c.user_id = 2 and c.contact_type = 1 and c.be_user_id = t.user_id
it is correct to use Union to write this
then use the left connection and I will not write, no matter how to write, there will be duplicate data
all I can think of is union
from the example you gave, if the end result takes only the data of the main table in the link and requires no repetition, you should not use the left join.
should use exists, such as:
select *
from a
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jav inserts Mysql data exception Data too long exception information 2018-04-24 00:15:01 ERROR com.comall.cybershop.common.base.DaoSupport org.springframework.dao.DataIntegrityViolationException: PreparedStatementCallback; SQL [update cs_awardCardRe...
select t.* from talk t where t.user_id = 2 Union select t.* from talk t, user_contact c where c.user_id = 2 and c.contact_type = 1 and c.be_user_id = t.user_id I don t want to use Union and I don t want to weigh it. Is there the easiest way to write...