Google/スプレットシート/関数/日付

8桁数字を日付に

20150101を2015/1/1へ

=floor(D2/10000)&"/"&floor(mod(D2,10000)/100)&"/"&MOD(D2,100)

20150101を2015-1-1へ

=floor(D2/10000)&"-"&floor(mod(D2,10000)/100)&"-"&MOD(D2,100)

20150101を2015-01-01へ

=mid(B33,1,4)&"-"&mid(B33,5,2)&"-"&mid(B33,7,2)

月末

今月末

=EOMONTH("2020-10-10",0)

翌月末

=EOMONTH("2020-10-10",1)

前月末

=EOMONTH("2020-10-10",-1)

unixtimeに変換

A1に"2024-10-10 10:10:10"

=(DATEVALUE(A1) + TIMEVALUE(A1) - DATE(1970,1,1)) * 86400

生年月日から年齢

=datedif("2021/10/3", today(),"y")

yyyy-mm-dd hh:ii:ss形式で表示

=TEXT(J3, "yyyy-mm-dd hh:mm:ss")