Re: Concatenate 2 Column Values For One Column - Mailing list pgsql-general

On 05/08/2018 07:17 PM, tango ward wrote:

Hi,

Sorry for asking question again.

I am trying to concatenate the value of column firstname and lastname from source DB to name column of destination DB.

My code so far:

cur_t.execute("""
                 SELECT firstname, lastname
                 FROM authors;
                 """)

for row in cur_t:
     cur_p.execute("""
                      INSERT INTO lib_author (
                                                  created, modified, last_name,
                                                  first_name, country,
                                                  school_id, name)
                     VALUES (current_timestamp, current_timestamp, %s, %s, %s,
                             (SELECT id FROM ed_school WHERE name='My Test School'),
                             (SELECT CONCAT(first_name, ',', last_name) AS name FROM lib_author LIMIT 1)
                             )
                     """, (row['lastname'], row['firstname'], ''))

The code will take the first and lastname of the FIRST data existing on the destination table. I modified the code, instead of running SELECT and CONCAT, I passed string formatter and call the row['firstname'], row['lastname']

for row in cur_t:
     cur_p.execute("""
                      INSERT INTO lib_author (
                                                  created, modified, last_name,
                                                  first_name, country,
                                                  school_id, name)
                     VALUES (current_timestamp, current_timestamp, %s, %s, %s,
                             (SELECT id FROM ed_school WHERE name='My Test School'),
                              %s
                             )
                     """, (row['lastname'], row['firstname'], '', (row['firstname'], row['lastname']) )

The second code works but it includes the parenthesis in the DB.

That is because:

(row['firstname'], row['lastname'])

is making a Python tuple for entry into the last %s.

Not tested but try:

(row['firstname'] + ', ' + row['lastname'])

How can I remove the ( ) in the DB? I can't call the row['firstname'] and row['lastname'] as values without using ( ).

Any suggestion is highly appreciated.

Thanks,
J

--
Adrian Klaver
adrian.klaver@aklaver.com