Compatibility
POSITION(s1 IN s2)
Engine	OK	Alternative
ingres	Yes
mysql	Yes
oracle	No	INSTR(s2,s1)
postgres	Yes
sqlserver	No	PATINDEX('%'+s1+'%',s2)

POSITION

POSITION(s1 IN s2) returns the character position of the substring s1 within the larger string s2. The first character is in position 1. If s1 does not occur in s2 it returns 0.

   POSITION('ll' IN 'Hello world') -> 3

In this example you return the position of the string 'an' within the name of the country.

SELECT name,
       PATINDEX('%an%', name)
  FROM bbc
 ORDER BY name

SELECT name,
       INSTR(name, 'an')
  FROM bbc

SELECT name,
       POSITION('an' IN name)
  FROM bbc