TYPO3: Condition "if column empty"? - typo3

Question

I'm looking for a condition to check wether a certain column is empty.
Something like this:
[colPos.0 = empty]
#do stuff
[global]
Thanks in advance.
Edit:
I think it's quite unclear what I'm looking for. So let me add some information:
I've got a column for a teaser image in the BE (colPos = 0). If it contains an element, it should regularly display this element. If not (== if empty), it should use another image instead.

Answer 1

There is of course a possibility to show stuff wether a Column has content or not,
but there is no TS-condition for this.
based on https://kuttler.eu/en/post/change-template-if-content-exists-in-typo3/,
here is my solution for this:
temp.foo {
temp.foo = COA
10 = COA
10 {
10 < styles.content.get
10.select.where = colPos=1
# conditional to test if content exists in column
if.isTrue.numRows {
# check current page page
pidInList = this
# in the table tt_content
table = tt_content
# colPos = 1
select.where = colPos=1
}
}
20 = COA
20 {
10 < lib.somethingElse
# conditional to test if content exists in column
if.isFalse.numRows {
# check current page page
pidInList = this
# in the table tt_content
table = tt_content
# colPos = 1
select.where = colPos=1
}
}
}
if.isTrue and if.isFalse are doing the trick here.
HTH

Answer 2

You can use if function, sample (from doc):
page.10 = COA_INT
page.10.10 = TEXT
page.10.10 {
stdWrap.if.isNull.field = description
value = No description available.
}
Edit: Also, if you are using Fluid template, you can just use f:if condition.