Regular Expressions 101

Non-Capturing Group(?: " \s* (?= (?: SELECT | FROM ) ) | (?<! ^ ) \G )

1st Alternative " \s* (?= (?: SELECT | FROM ) )

" the literal text "

\s*any whitespace character, repeated any number of times

Positive Lookahead(?= (?: SELECT | FROM ) )

Non-Capturing Group(?: SELECT | FROM )

1st Alternative SELECT

SELECT the literal text SELECT (case sensitive)

2nd Alternative FROM

FROM the literal text FROM (case sensitive)

2nd Alternative (?<! ^ ) \G

Negative Lookbehind(?<! ^ )

^start of string

\Gstart of current search

Negated Character Class[^"]*?

*?matches any number of characters outside the set below:

"the literal " (34₁₀ / 42₈ / 22₁₆)

\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match

Group 1( SELECT | FROM )

1st Alternative SELECT

SELECT the literal text SELECT (case sensitive)

2nd Alternative FROM

FROM the literal text FROM (case sensitive)

Comment: (1)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?:
     " \s* 
     (?=
          (?: SELECT | FROM )
     )
  |  
     (?<! ^ )
     \G 
)
[^"]*? 
\K 
( SELECT | FROM )             # (1)

New


    SELECT * FROM main -- will not match (not in a string)
    "SELECT name FROM main" -- will match
    "
    SELECT name FROM main" -- will match
    """Here is a SQL statement:

SELECT * FROM main""" -- no, string does not start with a keyword (SELECT...).

"SELECT * FROM table"
"
     SELECT * FROM table"

Regular Expression

Extraction