1. Interceptar por marca
#取左侧第三个下划线左侧的数据
SELECT substring_index(scenario,'_',3) FROM test_list where scenario = 'AVW_14_4_1_64.xml';
#结果:AVW_14_4
#取右侧第三个下划线右侧的数据
SELECT substring_index(scenario,'_',-3) FROM test_list where scenario = 'AVW_14_4_1_64.xml';
#结果:4_1_64.xml
2. Aninhamento de interceptação bit a bit
#先取左侧第三个下划线左侧 得 AVW_14_4 , 再取右侧第一个下划线右侧 得 4
SELECT substring_index(substring_index(scenario,'_',3),'_',-1) FROM test_list where scenario = 'AVW_14_4_1_64.xml';
#结果:4
3. Julgamento após interceptação
#如果截取后长度为2则取字符串左侧数据 否则直接赋值
UPDATE test_list
SET speed =
IF
(
LENGTH( substring_index( substring_index( scenario, '_',- 1 ), '.', '1' ) ) = 2,
left(substring_index( substring_index( scenario, '_',- 1 ), '.', '1' ),'1') ,
substring_index( substring_index( scenario, '_',- 1 ), '.', '1' )
);