![]() ![]() In the above examples, we have used the following regular expressions. Now, we will remove all digits from the above string by using the following statement: SELECT REGEXP_REPLACE('xyz54321ABC', Now, we will remove all alphabets characters from the above string by using the following statement: SELECT REGEXP_REPLACE('xyz54321ABC', Illustrate the result of the above statement by using the following snapshot.Įxample, to remove the string, consider we have a string in the following as follows: "xyz54321ABC" So, we can use the PostgreSQL REGEXP_REPLACE() function to do this as follows: SELECT REGEXP_REPLACE('Jacob David', Suppose we want to re-arrange the last name and the first name for purposes like the last name and then the first name. Here are the following examples of implementing the PostgreSQL REGEXP_REPLACE function Example #1 – Example to arrange the nameĬonsider the following name format like the first name and then last name: Replace_string: This string defines a string that replaces the substring, which matches the POSIX regular expression pattern.flags: This flag is used to control the behavior of the REGEXP_REPLACE() function, This can have the value of one or more characters.regex_pattern: This defines the POSIX regular expression to match the string.input_string: This defines the input string in which replacement should be taken place for a specified pattern, a POSIX regular expression.Then use it in whatever part of your query that makes sense.REGEXP_REPLACE(input_string, regex_pattern, replace_string,) This will output: REGEXP_REPLACE(REGEXP_REPLACE('input test string, 'test', '', 'gi'), 'foo', '', 'gi') So that finally, when no more substrings are in the list to remove, the final aggregated query is returned. Then, recursively calls the function again with elements and append each REGEXP query to the passed parameter. The code splits the comma separated string to a list of substrings to remove, Creates a REGEXP_REPLACE function in sql with the first substring. Replace_psql_string("test,foo", "input test string") Return self.replace_psql_string(','.join(ss), query) This is a generic recursive function written in python (but can easily be replicated in whatever language you prefer) That takes in the original string and a list of substrings to be removed: def replace_psql_string(str_to_remove, query): ![]() Replace characters with multi-character strings The result of the update is following: Juhanao Updates table so all predefined letters are translated and the change is saved to the database. update xyz set name = translate(name, 'ä,ü,Ü', 'a,u,U') Translates all letters ä to a, ü to u and Ü to U. ![]() The result of the update is following: JuhaenaeoĮxample of translate function: select translate(name, 'ä,ü,Ü', 'a,u,U') from xyz update xyz set name = replace(replace(replace(name, 'ä', 'ae'), 'ü', 'ue'), 'Ü', 'Ue') Ĭhanges letters and updates rows. Not very nice, but in the example all ä become ae, ü become ue, and Ü become 'Ue'. select replace(name, 'ä', 'ae') from xyz This function replaces letter ä in the name column with letter a. Some data to play with: drop table if exists xyz Įxample of replace function: select replace(name, 'ä', 'a') from xyz If you want to translate some letters to other letters you can user function translate(string text, from text, to text) that replaces any character in a string that matches a character in the from by the corresponding character in the to set. The replace function can be used to replace one character to several characters. If you want just to replace one or few characters you can use function replace(string text, from text, to text) that replaces all occurrences in string substring.
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