One of mysql Learning

One of mysql learning explain SQL statements: Query time consumed select version (): View mysql version show profiles: Analyze SQL Performance set profiling = 1: Turn on the profiles function, show profile for query x is disabled by default (x is query_id): it takes time to view the detailed time of a query based on query_id. show profile block io, cpu, memory, swaps, source, context switches for query x (x is query_id): View cpu usage, io, and other information 1. clear cache reset query cache; flush tables; 2. view the table index: show index from table name;