mysql - Insert data into table with result from another select query

Question

I am seeking help on the following issue: I have two tables Table_1 columns are itemid, locationid, quantity

Table_2 columns are itemid, location1, location2, location3

I want to copy data from Table_1 (only quantity column) into Table_2 (into location1 column). The itemid are same in both the tables(Table_1 has duplicate item id's) so that's the reason I want to copy to a new table and keep all quantity in one single row with each location as a column. I am using the below query but it doesn't work

INSERT INTO 
Table_2(location1) 
(
 SELECT qty 
 FROM Table_1 
 WHERE locationid = 1 AND Table_1.locationid = Table_2.locationid
)

Answer 1

If table_2 is empty, then try the following insert statement:

insert into table_2 (itemid,location1) 
select itemid,quantity from table_1 where locationid=1

If table_2 already contains the itemid values, then try this update statement:

update table_2 set location1=
(select quantity from table_1 where locationid=1 and table_1.itemid = table_2.itemid)