sql 如何使用SQL确定字符串的长度？

Posted 2021-05-13

---------------SQL Server---------------------------------------
select 

'I love you' as phrase,
len('I love you') as phrase_length,
len(' I love you ') as phrase_length2,
datalength(' I love you ') as phrase_length3

phrase     |phrase_length |phrase_length2 |phrase_length3 |
-----------|--------------|---------------|---------------|
I love you |10            |11             |12             |

--------------MySQL----------------------------------------------
select 

'I love you' as phrase,
length('I love you') as phrase_length

phrase     |phrase_length |
-----------|--------------|
I love you |10            |

--------------PostgreSQL-----------------------------------------
select 

'I love you' as phrase,
length('I love you') as phrase_length


phrase     |phrase_length 
-----------|--------------
I love you |10