178
169
insert ignore into t1 values(NULL,100),(NULL,110),(NULL,120);
179
170
insert ignore into t1 values(NULL,10),(NULL,20),(NULL,110),(NULL,120),(NULL,100),(NULL,90);
180
171
insert ignore into t1 values(NULL,130),(NULL,140),(500,110),(550,120),(450,100),(NULL,150);
181
175
select * from t1 order by id;