An error occurred when MySQL used leftjoin

Question

When I use the left join in mysql, there are two pieces of data, but I'm sure only one will come out

sql is

SELECT bs.id,distribute_user_id,manager_id,phone,manager_name 
FROM   bank_integral_distribute_serial bs 
         LEFT JOIN manager mi ON bs.distribute_user_id = mi.manager_id 
WHERE bs.phone = "13978836385"

Respective data sql is

SELECT  * 
FROM    bank_integral_distribute_serial 
WHERE   distribute_user_id="1475118915817316353"

sql is

SELECT  * 
FROM    manager 
WHERE   manager_id = "1475118915817316353"

I also check the mobile phone number, and there is only one

enter image description here

Questions: Why are there two pieces of data

Answer 1

The reason is that the MySQL comparison types are inconsistent.

you can see

https://dev.mysql.com/doc/refman/5.7/en/type-conversion.html

distribute_user_id The original table is bigint : manager_id is varchar

SELECT IF("1475118915817316353"=1475118915817316354,"equal","unequal") //The results are equal

SELECT IF("1475118915817316311"=1475118915817316360,"enqual","unequal") //The results are equal

//left?[1475118915817316224?1475118915817316480] The results are equal, both with the right side
SELECT IF("1475118915817316480"=1475118915817316360,"enqual","unenqual")