KB 102800
Function replace FIRSTDATE/LASTDATE with MIN/MAX
When FIRSTDATE or LASTDATE functions are used to return a scalar value instead of a table, the same result can be obtained in a more efficient way by using MIN or MAX on the column.
Remarks
FIRSTDATE and LASTDATE are table functions that internally use MIN and MAX, respectively.
Whenever the expression requires a scalar value, using the table function is unnecessarily expensive, also because it could involve a context transition in case one or more row contexts are active.
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Example 1
Original code
VAR firstDate = FIRSTDATE( Sales[Order Date] )
Possible optimization
VAR firstDate = MIN( Sales[Order Date] )
Example 2
Original code
CALCULATE (
LASTDATE( Sales[Order Date] ),
Customer[Country] = "Canada"
)
Possible optimization
CALCULATE (
MAX( Sales[Order Date] ),
Customer[Country] = "Canada"
)