Query varchar date with between

问题

How can i select a date stored as varchar (format: "2012.04") with the BETWEEN operator?

I need to select a one year interval on this field.

Now i'm trying with this, but this gives my MySQL syntax error:

SELECT DISTINCT monthcol
FROM bo_alerts
WHERE STR_TO_DATE(monthcol , '%Y.%m') BETWEEN
           (STR_TO_DATE('2012.04', '%Y.%m') AND STR_TO_DATE('2011.03', '%Y.%m'))
ORDER BY monthcol DESC

The dates are now static (for testing), but i need to calculate the second value in the BETWEEN so that it will be exact -1 year to the first value of the BETWEEN section.

Thank you very much!!

回答1:

Given that the dates seem to be fixed length strings, why not use string comparison?:

SELECT DISTINCT monthcol
FROM bo_alerts
WHERE monthcol BETWEEN '2011.03' AND '2012.04'
ORDER BY monthcol DESC

Notice that I reversed the order of the dates to satisfy most SQL implementations having the first less than the second.

回答2:

Renove '.' from date it will work.

Try below query :

SELECT DISTINCT monthcol 
FROM bo_alerts 
WHERE concat(LEFT(monthcol,4),RIGHT(monthcol,2)) BETWEEN 201204  AND 201103
ORDER BY monthcol DESC

来源：https://stackoverflow.com/questions/10206117/query-varchar-date-with-between