Cursor not populating while using max in sqlite












0














I have a database like following



datetime    value
date1 200
date2 230
date3 210
date4 240
date5 220


I find out the rowid for the column of which I want to dynamically find out the max value for the 2 rows above
Say I found 4 for date4, I want to calculate the maximum of values 230,210 and 240 which is 240



I give the following command



c.execute("SELECT MAX(value) FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


The problem is cursor doesn't populate and returns an empty list while in



c.execute("SELECT value FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


it returns the correct values of the 3 rows (3 tuples in a list). Can I not use limit with max? What is the problem? Do I have to make another int column equivalent to rowid for querying well and use an order by numberingColumn or is there a better solution?










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  • 1




    Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
    – Shawn
    Nov 13 at 21:44
















0














I have a database like following



datetime    value
date1 200
date2 230
date3 210
date4 240
date5 220


I find out the rowid for the column of which I want to dynamically find out the max value for the 2 rows above
Say I found 4 for date4, I want to calculate the maximum of values 230,210 and 240 which is 240



I give the following command



c.execute("SELECT MAX(value) FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


The problem is cursor doesn't populate and returns an empty list while in



c.execute("SELECT value FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


it returns the correct values of the 3 rows (3 tuples in a list). Can I not use limit with max? What is the problem? Do I have to make another int column equivalent to rowid for querying well and use an order by numberingColumn or is there a better solution?










share|improve this question


















  • 1




    Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
    – Shawn
    Nov 13 at 21:44














0












0








0







I have a database like following



datetime    value
date1 200
date2 230
date3 210
date4 240
date5 220


I find out the rowid for the column of which I want to dynamically find out the max value for the 2 rows above
Say I found 4 for date4, I want to calculate the maximum of values 230,210 and 240 which is 240



I give the following command



c.execute("SELECT MAX(value) FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


The problem is cursor doesn't populate and returns an empty list while in



c.execute("SELECT value FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


it returns the correct values of the 3 rows (3 tuples in a list). Can I not use limit with max? What is the problem? Do I have to make another int column equivalent to rowid for querying well and use an order by numberingColumn or is there a better solution?










share|improve this question













I have a database like following



datetime    value
date1 200
date2 230
date3 210
date4 240
date5 220


I find out the rowid for the column of which I want to dynamically find out the max value for the 2 rows above
Say I found 4 for date4, I want to calculate the maximum of values 230,210 and 240 which is 240



I give the following command



c.execute("SELECT MAX(value) FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


The problem is cursor doesn't populate and returns an empty list while in



c.execute("SELECT value FROM TABLE LIMIT "+str(rowid-2)+",3")
print(c.fetchall())


it returns the correct values of the 3 rows (3 tuples in a list). Can I not use limit with max? What is the problem? Do I have to make another int column equivalent to rowid for querying well and use an order by numberingColumn or is there a better solution?







python sqlite sqlite3






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asked Nov 13 at 20:57









caissalover

259




259








  • 1




    Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
    – Shawn
    Nov 13 at 21:44














  • 1




    Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
    – Shawn
    Nov 13 at 21:44








1




1




Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
– Shawn
Nov 13 at 21:44




Your first query returns a single row, which you say to skip with that offset of 3. Thus, no rows are returned.
– Shawn
Nov 13 at 21:44












1 Answer
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oldest

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Thank you @Shawn



c.execute("SELECT MAX(TEMPVALUE) FROM (SELECT value AS TEMPVALUE FROM TABLE LIMIT "+str(rowid+2)+",3)")


solved the problem!






share|improve this answer





















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    0














    Thank you @Shawn



    c.execute("SELECT MAX(TEMPVALUE) FROM (SELECT value AS TEMPVALUE FROM TABLE LIMIT "+str(rowid+2)+",3)")


    solved the problem!






    share|improve this answer


























      0














      Thank you @Shawn



      c.execute("SELECT MAX(TEMPVALUE) FROM (SELECT value AS TEMPVALUE FROM TABLE LIMIT "+str(rowid+2)+",3)")


      solved the problem!






      share|improve this answer
























        0












        0








        0






        Thank you @Shawn



        c.execute("SELECT MAX(TEMPVALUE) FROM (SELECT value AS TEMPVALUE FROM TABLE LIMIT "+str(rowid+2)+",3)")


        solved the problem!






        share|improve this answer












        Thank you @Shawn



        c.execute("SELECT MAX(TEMPVALUE) FROM (SELECT value AS TEMPVALUE FROM TABLE LIMIT "+str(rowid+2)+",3)")


        solved the problem!







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 14 at 10:30









        caissalover

        259




        259






























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