That’s pretty much all you need: mysql> select * from t; +——+——-+ | id | data | +——+——-+ | 1 | max | | 2 | linda | | 3 | sam | | 4 | henry | +——+——-+ 4 rows in set (0.02 sec) mysql> update t set data=concat(data, ‘a’); Query OK, 4 rows … Read more
You can concatenate strings a number of ways: let a = “Hello” let b = “World” let first = a + “, ” + b let second = “\(a), \(b)” You could also do: var c = “Hello” c += “, World” I’m sure there are more ways too. Bit of description let creates a … Read more
convert the NULL values with empty string by wrapping it in COALESCE SELECT CONCAT(COALESCE(`affiliate_name`,”),’-‘,COALESCE(`model`,”),’-‘,COALESCE(`ip`,”),’-‘,COALESCE(`os_type`,”),’-‘,COALESCE(`os_version`,”)) AS device_name FROM devices
MySQL is different from most DBMSs’ use of + or || for concatenation. It uses the CONCAT function: SELECT CONCAT(first_name, ‘ ‘, last_name) AS Name FROM test.student There’s also the CONCAT_WS (Concatenate With Separator) function, which is a special form of CONCAT(): SELECT CONCAT_WS(‘ ‘, first_name, last_name) from test.student That said, if you want to … Read more
Given that all the dataframes have the same columns, you can simply concat them: import pandas as pd df = pd.concat(list_of_dataframes)
You can use GROUP_CONCAT: SELECT person_id, GROUP_CONCAT(hobbies SEPARATOR ‘, ‘) FROM peoples_hobbies GROUP BY person_id; As Ludwig stated in his comment, you can add the DISTINCT operator to avoid duplicates: SELECT person_id, GROUP_CONCAT(DISTINCT hobbies SEPARATOR ‘, ‘) FROM peoples_hobbies GROUP BY person_id; As Jan stated in their comment, you can also sort the values before … Read more