How can I copy data from one column to another in the same table?
SqlSql Problem Overview
Is it possible to copy data from column A to column B for all records in a table in SQL?
Sql Solutions
Solution 1 - Sql
How about this
UPDATE table SET columnB = columnA;
This will update every row.
Solution 2 - Sql
UPDATE table_name SET
destination_column_name=orig_column_name
WHERE condition_if_necessary
Solution 3 - Sql
This will update all the rows in that columns if safe mode is not enabled.
UPDATE table SET columnB = columnA;
If safe mode is enabled then you will need to use a where clause. I use primary key as greater than 0 basically all will be updated
UPDATE table SET columnB = columnA where table.column>0;
Solution 4 - Sql
If you want to copy a column to another column with a different data type in PostgresSQL, you must cast/convert to the data type first, otherwise it will return
> Query 1 ERROR: ERROR: column "test_date" is of type timestamp without > time zone but expression is of type character varying LINE 1: update > table_name set test_date = date_string_col > ^ HINT: You will need to rewrite or cast the expression.
An example of converting varchar to timestamp:
update table_name set timestamp_col = date_string_col::TIMESTAMP;
An example of converting varchar to int:
update table_name set int_column = string_col::INTEGER;
but any column type(except file or the similar) can be copied to string(character varying) without cast the type.