Differences from SQL

Metadata search queries are similar to the WHERE clauses of SQL queries, but they differ in that:

• Metadata search queries follow the PCRE (Perl-Compatible Regular Expression) format.

• Metadata search queries do not require values with hyphens to be enclosed in backticks, (`)

  • SQL query

    `x-amz-meta-search-item` = `ice-cream-cone`
    

  • Metadata Search query

    x-amz-meta-search-item = ice-cream-cone
    

• Metadata search queries do not support all SQL operators.

  • Supported SQL operators: =, <, >, <=, >=, !=, AND, OR, LIKE, and <>
  • Unsupported SQL operators: NOT, BETWEEN, IN, IS, +, -, %, ^, /, *, and !

Using Regular Expressions in Metadata Search

• Regular expressions used in metadata search differ from SQL in that wild cards are represented with .* instead of %.
• Regex patterns must be wrapped in quotes. Failure to do this can lead to pattern misinterpretation.
• Regex patterns can be written in the /pattern/ syntax or simply as the pattern if regex options are not required, similar to PCRE.

The following searches, for example, return strings containing the substring “helloworld”

".*helloworld.*"

"/.*helloworld.*/"

"/.*helloworld.*/i"