Newbie needs help on query (MYSQL) - mysql

Question

I'm new here and nearly new in SQL.
My problem:
I've a table (T1) with
Datetime, CostNo, Amount
second table (T2) with
Date, CostNo, BillNo
In the query should be
Date, CostNo, BillNo, Amount
My problem are several BillNos for the same CostNo the same day.
I need a kind of sorting the BillNo according to the Datetime.
T1 f.e.:
2018-11-02 11:14:52 3637 24.10
2018-11-02 11:16:43 965 2.50
2018-11-02 11:40:28 2552 3.50
2018-11-02 11:40:51 2552 3.00
2018-11-02 11:41:10 2552 3.50
2018-11-02 11:41:36 2552 3.00
2018-11-02 11:55:03 980 3.00
2018-11-02 11:59:11 1976 3.00
T2 f.e.:
2018-11-02 3637 26189
2018-11-02 965 26190
2018-11-02 2552 26191
2018-11-02 2552 26192
2018-11-02 2552 26193
2018-11-02 2552 26194
2018-11-02 980 26195
2018-11-02 1976 26196
so my query:
select
T2.BillDate,
T2.CostNo,
T2.BillNo,
T1.Amount
from
`T2`,
`T1`
where
T1.CostNo =T2.CostNo
AND DATE(T1.BillDateTime) = T2.BillDate
works fine until CostNo 2552:
2018-11-02 3637 26189 24.10
2018-11-02 965 26190 2.50
2018-11-02 2552 26191 3.50
2018-11-02 2552 26191 3.00
2018-11-02 2552 26191 3.50
2018-11-02 2552 26191 3.00
2018-11-02 2552 26192 3.50
2018-11-02 2552 26192 3.00
2018-11-02 2552 26192 3.50
2018-11-02 2552 26192 3.00
2018-11-02 2552 26193 3.50
2018-11-02 2552 26193 3.00
2018-11-02 2552 26193 3.50
2018-11-02 2552 26193 3.00
2018-11-02 2552 26194 3.50
2018-11-02 2552 26194 3.00
2018-11-02 2552 26194 3.50
2018-11-02 2552 26194 3.00
2018-11-02 980 26195 3.00
2018-11-02 1976 26196 3.00
This should be the result:
2018-11-02 3637 26189 24.10
2018-11-02 965 26190 2.50
2018-11-02 2552 26191 3.50
2018-11-02 2552 26192 3.00
2018-11-02 2552 26193 3.50
2018-11-02 2552 26194 3.00
2018-11-02 980 26195 3.00
2018-11-02 1976 26196 3.00

Answer 1

I am guessing that you want:
select T2.BillDate, T2.CostNo, T2.BillNo, T1.Amount
from `T2` join
`T1`
on T1.CostNo = T2.CostNo and DATE(T1.BillDateTime) = T2.BillDate
order by T!.CostNo, T1.BillDateTime DESC;
First note the proper use of JOIN. Never use commas in the FROM clause. Always use proper, explicit, standard JOIN syntax.
Second, if you want the results in a particular order, then your query should have an ORDER BY clause. SQL tables and result sets (with no ORDER BY) represent unordered sets. So, you need an ORDER BY. I am guessing you want to keep all the CostNos together, and then within each, ordered by the date/time.

Answer 2

OK thanks for the help. I found a solution by myself.
Here it is, if someone will know it:
The BillNo from the 2. table is linked to the DateTime of table 1
So I build a temporaray table from table 1 with SUM/GROUP BY and ORDER BY on DateTime and add a row ID (auto_increment).
Next I build a temporary table from table 2, order by BillNo and add a row ID.
Now I can do a query with T1.ID = T2.ID and that's it.
Feel free to post a better and/or shorter solution.