SQL query to find last day code was used

Question

I want to run a query to find out the last day a code was used by each Company.

SELECT T1.comp, T1,code, T1 date
FROM T1

I want to add MAX to T1.date but unsure of the sytax ... or something similar

Perhaps I can create a DATE field by concatenating T1.period & T1,yr but struggle with syntax ..

DateValue(Str(T1.period) & Str(T1.yr))

Much appreciated!

Answer 1

Order the table on the date descending, and keep only the first row:

SELECT TOP 1 T1.comp, T1.code, T1.date
FROM T1
ORDER BY T1.date DESC

Answer 2

You need an aggregate function. you can find more details here: http://www.sqlcourse2.com/agg_functions.html

for the mean time try:

SELECT T1.comp, max(T1 date)
FROM T1
GROUP BY t1.comp

Answer 3

By the comments on @ThomasG answer I assume you want the max for each comp that has more then 300 records?

If so, use GROUP BY and HAVING :

SELECT T1.comp, max(T1 date)
FROM T1
GROUP BY t1.comp
HAVING COUNT(*) >= 300

Answer 4

try this,

SELECT T1.comp, T1.code, MAX(T1.date) AS LastDate
FROM T1
GROUP BY T1.comp, T1.code