sqlite3 - SQL - Updating a column based on values from another query -

sqlite3 - SQL - Updating a column based on values from another query -

still new sql. goal find lastly time stamp event , update lastly session column per user. created query able find lastly time stamp each user in database. want update property_last_session_date based on property_user_id

i'm running off sqlite3 , 3 columns defined varchar(255)

here code i'm trying run.

update tb1 set tb1.property_last_session_date = tt1.property_timestamp tableevents tb1 bring together (select tb2.property_user_id, max(tb2.property_timestamp) tableevents tb2 grouping tb2.property_user_id) tt1 on tb1.property_user_id = tt1.property_user_id

thank help!

update tb1 set tb1.property_last_session_date = (select tt1.property_timestamp (select tb2.property_user_id, max(tb2.property_timestamp) property_timestamp tableevents tb2 grouping tb2.property_user_id) tt1 tb1.property_user_id = tt1.property_user_id);

it's called correlated subquery, may utilize in select, update, delete.

note subquery executed each row of tb1.

however, mysql should smart plenty execute tt1 once.

this query update rows in tb1. there can problems rows tb1.property_user_id null (tb1.property_last_session_date set null)

update tb1 set property_last_session_date = (select prop_time (select property_user_id user_id, max(property_timestamp) prop_time tableevents tb2 grouping property_user_id) tt1 tt1.user_id = property_user_id);

sql sqlite3