Regex is that will match commented SQL code

Question

How to write a Java regular expression for a commented SQL code like below?

/*
    SELECT * FROM Table1;
    -- Comment in comment
    Another SQL code
*/
SQL-code
-- One line comment
/**/ -- Yet one comment
/* And yet one comment */

This is my current wrong variant: (--.*)|(/\*(.*\n)*\*/).

I know that comment signatures (--, /**/) can be inside string but for my purpose we can consider so strings as comments, it doesn't matter. The most important to exclude all commented SQL code.

@VLAZ nope, to build diagram from procedures which tables are used inside procedure body, so I need to remove commented SQL code to analyzer didn't extract table names from comments. — Denis Steinman
– Denis Steinman, Commented Nov 19, 2019 at 9:38

Michał Turczyn · Accepted Answer · 2019-11-19 09:50:57Z

2

Try this pattern for matching comments:

(?s)(?:\/\*.*?\*\/|--[^\n]*)

Explanation:

(?s) - single line mode, . matches newline

(?:...) - non-capturing group

\/\* - match /* literally

.*? - match zero or more of any characters (non-greedy)

\*\/ - match */ literally

| - alterantion - match pattern on the left side or on the right side of it

-- - match -- literally

[^\n]* - match zero or more characters other from newline character

Demo

answered Nov 19, 2019 at 9:50

Michał Turczyn

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1 Comment

Denis Steinman Over a year ago

Thank you, for my task it works perfectly. And special thank for explanation)

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