mysql-display different columns from multiple tables - mysql

Question

Consider the following table and values..i need to display all the column and its values from table "TAG" along with single column value from another table named as "ITEM"
TABLE NAME "TAG"
TAGID NAME RATE
1 A 100
2 B 200
3 C 300
4 D 8099
5 E 400
6 F 500
7 G 600
8 H 700
9 I 200
10 J 400
TABLE NAME "ITEM"
ITEMID Name ITEM_QTY
1 A 11
2 B 22
3 I 3
4 A 8
5 B 42
6 C 5
7 I 61
8 B 74
9 C 99
10 A 48
EXPECTED OUTPUT
TAGID NAME RATE ITEM_QTY
1 A 100 48 - (VALUE OF LAST INSERTED RECORD)
2 B 200 74
3 C 300 99
4 D 8099 0
5 E 400 0
6 F 500 0
7 G 600 0
8 H 700 0
9 I 200 61
10 J 400 0
i have tried some sort of quires but its all vien..
this is my query,
select *
from tag t1
join ( select item_qty
from item t2
join tag t1
on t1.name=t2.name;
can anyone pls help me out of this issue...
thanks in advance...

Answer 1

try like this
select tag.id,tag.name,rate,qty from tag join
(select qty,name from
ITEM where ITEM.id in
(select max(id) from ITEM group by name)) as tt on tt.name=tag.name

Answer 2

Assuming, that the last inserted record has the highest ID in your item table, you first need to get the highest ID per item name.
SELECT
Name, MAX(ITEMID) AS max_id
FROM
item
GROUP BY Name;
With this query (executed in the following query as subquery) we get the corresponding row for each max_id.
SELECT i.*
FROM item i
JOIN (
SELECT
MAX(ITEMID) AS max_id
FROM
item
GROUP BY Name
) si ON i.ITEMID = si.max_id;
Here are more examples of how to get The Rows Holding the Group-wise Maximum of a Certain Column.
The final query is
SELECT TAGID, tag.NAME, RATE, COALESCE(ITEM_QTY, 0) AS ITEM_QTY
FROM
tag
LEFT JOIN (
SELECT i.*
FROM item i
JOIN (
SELECT
MAX(ITEMID) AS max_id
FROM
item
GROUP BY Name
) si ON i.ITEMID = si.max_id
) items ON tag.Name = items.Name
see it working live in an sqlfiddle

Answer 3

You may try as
select
t.tagid,
t.name,
t.rate,
i.item_qty
from tag t
join
(
select name,max(item_qty) as item_qty
from item group by name
)i
on i.name = t.name
DEMO
If you need all the data from item table as you have shown in the output you may use left join instead of inner join
select
t.tagid,
t.name,
t.rate,
coalesce(i.item_qty,0) as item_qty
from tag t
left join
(
select name,max(item_qty) as item_qty
from item group by name
)i
on i.name = t.name
DEMO