Dynamically update/assign @parameter in query
I've got a query which passes correctly in mysql.
Problematic in FastReport query window is:
@SecI := t.TimestampCol AS ChangeTime
This line is not a static parameter assignment but its being used as a dynamically updated variable for:
IF(@SecI = 0, 0, TIMESTAMPDIFF(SECOND, @SecI, t.TimestampCol)) AS SecI
@SecI is initialized in the query as: SELECT @SecI := 0
Both cases of using ":=" (colon-equal-sign- /assignment-) operator together with @ (at-operator) operator result in an error.
On "define parameter" page within FastReport query wizard @SecI is defined as double with default value zero.
I could probably go with:
1) "Expression" an create my "@SecI := t..." dataset elsewhere and reference it my original query
2) Rewrite the query to calculate SecI differently
But: I am interested in this specific self-consistent implementation.
Do you have any suggestions how to syntactically write this in a FastReport compatible way using the (":=") assignment operator?