SQL: Visual QuickStart Guide

Finding Substrings with POSITION()

Use the POSITION() function to locate a particular substring within a given string. The POSITION() function’s important characteristics are:

• POSITION() returns an integer (≥0) that indicates the starting position of a substring’s first occurrence within a string.

• If the string doesn’t contain the substring, POSITION() returns zero.

• String comparisons may be case-insensitive or case-sensitive, depending on your DBMS; see the DBMS Tip in “Filtering Rows with WHERE” in Chapter 4.

• The position of any substring within an empty string is zero.

• If any argument is null, POSITION() returns null. (But see the Oracle exception in the DBMS Tip in this section.)

To find a substring:

• Type:

  POSITION(substring IN string)