Get up-to-date data based on time SQL (per person or per item)

--Method 1SelectA.* fromtable1 awhereNot EXISTS (Select 1                    fromtable1 bwhereB.name=a.name and B.gdtime>a.gdtime)--Method 2SelectA.* fromtable1 a INNER join (Selectname, Max (gdtime)'Maxgdtime'   fromtable1 GROUP by name) B on A.name=b.name and A.gdtime=b.maxgdtime

After testing 3 million data queries, the Method 2 query is faster, and it is recommended to use the second kind of correlation query method

Get up-to-date data based on time SQL (per person or per item)