11/23/2023 0 Comments Postgresql find substring![]() The POSITION() function returns the location of the first instance of the substring in the string.Ĭonsider the following example: SELECT POSITION( 'is' IN 'This is a cat') Code language: JavaScript ( javascript )Įven though the substring 'is' appears twice in the string 'This is a cat', the POSITION() function just returned the first match. It returns zero (0), indicating that the string tutorial does not exist in the string 'PostgreSQL Tutorial'. See the following example: SELECT POSITION( 'tutorial' IN 'PostgreSQL Tutorial') Code language: JavaScript ( javascript ) Note that the POSITION() function searches for the substring case-insensitively. The following example returns the position of the 'Tutorial' in the string 'PostgreSQL Tutorial': SELECT POSITION( 'Tutorial' IN 'PostgreSQL Tutorial') Code language: JavaScript ( javascript ) It returns null if either substring or string argument is null. The POSITION() function returns zero (0) if the substring is not found in the string. The POSITION() function returns an integer that represents the location of the substring within the string. The string argument is the string for which the substring is searched. The substring argument is the string that you want to locate. The POSITION() function requires two arguments: The following illustrates the syntax of the PostgreSQL POSITION() function: POSITION(substring in string) Arguments So the characters are set to empty string.The PostgreSQL POSITION() function returns the location of a substring in a string. Yet another XXX010102 and this XXX010103 2 Something XXX010101 something else XXX010102 1 Let table B contain all the search texts you want text 2 val Let table A contain all possible combinations of XXX010101. INNER JOIN B ON B.Text2 LIKE ('%' || A.Text || '%') I'll make no claims as to good performance though. How about something like this (assuming the values you're looking for are contained in a separate table). This makes heavy use of a features of PostgreSQL's POSIX Regular Expressions (link to version 8.2!) ![]() In 8.2 you'll have to come up with something of your own. In PsotgreSQL 8.3+ you could use regexp_split_to_table() to split the wanted strings into single rows. to make that work use (XXX\\d+?,)*? to capture any number of leading occurances of wanted string.then globally replace everything in between wanted strings. ![]() so I terminate the wanted strings with a, after removing all other occurances of, Could be any character not part of the wanted strings, but, can serve as separator in the result.we cannot mix greedy and non-greedy quantifiers in the same regular expression.but there is regexp_replace() which can use a g flag (replace globally).no regex_matches() in version 8.2 as OP already stated.now we can use non-greedy terminated with "," The following demo should work with PostgreSQL 8.2: SELECT - content, Version 8.2 reaches end of live right now. I am somewhat hesitant to even post my answer. How would you go about solving this? Or is an upgrade my best bet? ) (it's a production system so the downtime and some risk of problems after migration is a source of hesitation ).įor "something XXX010101 something else XXX010102" When looking around I found that 8.3 introduced a regex_matches function that seems to be what I'd need - are there any alternatives in 8.2? Or an easy way to get it in 8.2? but to be true I hoped (and failed to find) for a simpler solution (like a g flag to substring). The one idea I have is to create some monster regex to replace everything that's not an XXX substring. parts from them - possibly using some separator if needed - right now I'm able to easily take out the first one using: select distinct substring(content from 'XXX+'), content from data where content ~ 'XXX+' I've got a table with entries that are similar to "something XXX010101 somethingelse XXX010102".
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