理论上，我认为这应该对你有用。
--第1部分：清除/创建临时表并将csv加载到sql中。感谢埃克莱尔先生在这里描述了这一过程

drop table #temp

create table #temp (
tName nvarchar(25),
tAge int, 
tLocation nvarchar(25),
tHeight float(3,2), -- alternatively, use cm instead of m and just use int(3)
tWeight int
)

BULK INSERT #temp
FROM 'C:\CSVData\updates.csv'
WITH
(
FIRSTROW = 2,
FIELDTERMINATOR = ',',  --CSV field delimiter
ROWTERMINATOR = '\n',   --Use to shift the control to next row
TABLOCK
)

--第二部分：设置唯一键；正如@yuri\u lachin所建议的

Alter table target
Add Unique (Name) -- Sets Name column as a Unique Key for the table target

--第3部分：从临时表向永久表添加行和更新值。MySQL5.7参考手册13.2.5.2

Insert into target(Name, Age, Location, Height, Weight)
Select tName, tAge, tLocation, tHeight, tWeight from #temp
On DUPLICATE KEY Update Weight = tWeight

我本来打算建议使用如下的merge语句，但看起来mysql没有处理这些问题。

Merge Into people
using #temp
on target.name = #temp.tname
when matched then Update
set target.weight = #temp.tweight
when not matched then 
Insert (target.name, target.age, target.location, target.height, target.weight)
values (#temp.tname, #temp.tage, #temp.tlocation, #temp.theight,  #temp.tweight);