db2 => select LOCATE('B','ABCD') from sysibm.sysdummy1

1          
-----------
          2

  1 record(s) selected.

db2 => select POSSTR('ABCD','B') from sysibm.sysdummy1

1          
-----------
          2

  1 record(s) selected.

db2 =>

db2 => select POSITION('B','ABCD',OCTETS) from sysibm.sysdummy1

1          
-----------
          2

  1 record(s) selected.

LOCATE的一个好处就是可以指定从哪个位置开始搜索

db2 => select LOCATE('B','ABCBD',3) from sysibm.sysdummy1

1          
-----------
          4

  1 record(s) selected.

db2 =>