MySQL：関数と演算子 #12

select 10-3;

select 10/3;

select 10-null; #null

select 10/null; #null

select abs(-10);#10

select id,name,round(price*1.08,0) from products;#少数第一位で四捨五入

select round(10.555,1);#10.6

select concat(last_name,'さん'),email from users where gender=2;

select current_date();#2019-01-03

select current_date()+3;#20190106

select current_time()+interval 6 hour;#27:58:11

 

select * from orders where extract(year from order_time)=2017;