A summary (foundation) after learning MySQL
1.To operate the mysql server at the command prompt, add system variables.(Computer-System Properties-Environment Variables-Path)
2.Query the data in the data table;
select selection_list select */columns
from table_list from table1/table2
where primary_constraint
group by grouping_columns
order by sorting_colomns desc descending order select * from table order by id desc;
having second_constraint
limit count select * from table where id limit 1,4;
2 Commonly used statistical functions: avg (field), sum (field), count (field), min (field),
select sum(field 2) as alias, field 1 from table group by field 1;
3 arithmetic operation, string, and logical operation construction expression: select * (price*0.8) as '80%' from table; 20% off
2.Query the data in the data table;
select selection_list select */columns
from table_list from table1/table2
where primary_constraint
group by grouping_columns
order by sorting_colomns desc descending order select * from table order by id desc;
having second_constraint
limit count select * from table where id limit 1,4;
2 Commonly used statistical functions: avg (field), sum (field), count (field), min (field),
select sum(field 2) as alias, field 1 from table group by field 1;
3 arithmetic operation, string, and logical operation construction expression: select * (price*0.8) as '80%' from table; 20% off
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