**1. 语法** ```sql label:LOOP statements END LOOP label - loop是一个死循环，跳出循环可以使用 leave:label 类似编程语言中的continue语句在 loop 中用 iterate:label ``` **2. 演示** ```sql create function fun_add_loop(count int) returns int begin declare sum int default 0; lo_label:loop set sum = sum + 1; set count = count - 1; if count <= 0 then leave lo_label; end if; end loop lo_label; return sum; end $ mysql> select fun_add_loop(5) $ +-----------------+ | fun_add_loop(5) | +-----------------+ | 5 | +-----------------+ ```