Is there a way to select all cells in a column above the current cell?.
The LibreOffice help page provides
Shift+Home = Selects cells from the current cell to the first cell of the current row.
but there doesn’t seem to be an equivalent for column selection. Nearest I can find is “Shift+Page Up” but this only selects cells up to the first empty cell.
Apologies if this is an obvious oversight on my behalf 
7.3.7.2 / LibreOffice Community
Build ID: 30(Build:2)
Linux 5.15
You may hold Shift+PgUp until the selection reaches the first cell of the column or use a simple macro:
Sub select_until_column_top()
oView = ThisComponent.getCurrentController()
oCell = getActiveCell(oView)
addr = oCell.getRangeAddress()
addr.StartRow = 0
rg = getRangeByAddress(ThisComponent, addr)
oView.select(rg)
End Sub
Function getRangeByAddress(obj, oAddr as com.sun.star.table.CellRangeAddress)
on error goto nullErr:
Dim oSheet
If obj.supportsService("com.sun.star.sheet.SpreadsheetDocument") then
REM use the sheet specified by given address
oSheet = obj.getSheets.getByIndex(oAddr.Sheet)
else
REM use given object (range/sheet) as parent range
oSheet = obj
endif
getRangeByAddress = oSheet.getCellRangeByPosition(oAddr.StartColumn,oAddr.StartRow,oAddr.EndColumn,oAddr.EndRow)
exit function
nullErr:
getRangeByAddress = Null
End Function
Function getActiveCell(Optional oView )
Dim as1(), lSheet&,lCol&,lRow$, sDum as String,bErr as Boolean
If isMissing(oView) then oView = ThisComponent.getCurrentController()
as1() = Split(oView.ViewData, ";")
lSheet = CLng(as1(1))
sDum = as1(lSheet +3)
as1() = Split(sDum, "/")
on error goto errSlash
lCol = CLng(as1(0))
lRow = CLng(as1(1))
on error goto 0
getActiveCell = oView.Model.getSheets.getByIndex(lSheet).getcellByPosition(lCol,lRow)
exit Function
errSlash:
if NOT(bErr) then
bErr = True
as1() = Split(sDum, "+")
resume
endif
End FunctionThe Shift-PgUp selects all cells for me in a column above the active cell.
LO 7.5.8
PgUp/Down jumps one screen full of cells. You may need to hold Shift+PgUp until the selection reaches the first cell.
I only get one page at a time, as @Villeroy mentions, but holding Shift+PgUp is pretty quick (only 5000 rows).
You may hold Shift+Ctrl+Up (which jumps to the next transition of empty/non-empty cells) until selected to the top. If all cells above are filled in the column it’s just a one time operation.
Similar with Shift+Ctrl+Left / Shift+Ctrl+Right / Shift+Ctrl+Down.