github.com/matrixorigin/matrixone@v1.2.0/test/distributed/cases/function/func_string_split_part.test (about)

     1  select split_part('axbxc','x',1);
     2  select split_part('axbxcxd','x',2);
     3  select split_part('axbxcxd','x',3);
     4  select split_part('axbxcxd','xc',1);
     5  select split_part('axbxcxd','xc',2);
     6  select split_part('axbxcxd','xc',3);
     7  select split_part('axbxcxd','asas',1);
     8  select split_part('axbxcxd','asas',2);
     9  select split_part(null,'asas',3);
    10  select split_part('axbxcxd',null,3);
    11  select split_part('axbxcxd','asas',null);
    12  select split_part('axxx','x',1);
    13  select split_part('axxx','x',2);
    14  select split_part('axxx','x',0);
    15  select split_part('axxx','x',-1);
    16  create table t1(a varchar,b varchar,c int);
    17  insert into t1 values('axbxc','x',1),('axbxcxd','x',2),('axbxcxd','x',3),('axbxcxd','xc',1),('axbxcxd','xc',2),('axbxcxd','xc',3),('axbxcxd','asas',1),('axbxcxd','asas',2),(null,'asas',3),('axbxcxd',null,3),('axbxcxd','asas',null),('axxx','x',1),('axxx','x',2);
    18  select split_part(a,b,c) from t1;
    19  insert into t1 values('axxx','x',0);
    20  select split_part(a,b,c) from t1;
    21  insert into t1 values('axxx','x',-1);
    22  select split_part(a,b,c) from t1;