Regular expressions

Regular expressions are a sequence of characters used to identify patterns in identifiers and string values. InfluxQL supports regular expressions in the following operations:

• Identifying fields and tags to query in the SELECT clause.
• Identifying measurements to query in the FROM clause.
• Testing tag values and string field values in the WHERE clause.
• Identifying tag keys to group by in the GROUP BY clause

Regular expression syntax

InfluxQL Regular expressions are surrounded by / characters and use the Go regular expression syntax.

/regular_expression/

Regular expression flags

Regular expression flags modify the pattern-matching behavior of the expression. InfluxQL supports the following regular expression flags:

Include regular expression flags at the beginning of your regular expression pattern enclosed in parentheses (()) and preceded by a question mark (?).

/(?iU)foo*/

Regular expression operators

InfluxQL provides the following regular expression operators that test if a string operand matches a regular expression:

• =~: Returns true if the string matches the regular expression
• !~: Returns true if the string does not match the regular expression

InfluxQL regular expression operators are used to test string column values in the WHERE clause.

Regular expression examples

The examples below use the following sample data sets:

• NOAA Bay Area weather data
• Get started home sensor data

SELECT /^t/ FROM weather

SELECT /^t/ FROM /^[hw]/

SELECT * FROM weather WHERE location !~ /^[S]/

SELECT * FROM home, weather WHERE location !~ /./

SELECT MAX(precip) FROM weather GROUP BY /^l/