Finding the Minimum Value of an Expression Using MINX in DAX

What Is MINX in DAX?

MINX is an iterator function in DAX that evaluates an expression for each row of a table and returns the smallest value produced by that expression.

The basic syntax is:

MINX(
    <Table>,
    <Expression>
)

The first argument specifies the table that MINX should iterate through. The second argument is the expression that DAX evaluates for each row.

1. Retrieving the Source Table

Query

EVALUATE
    MaxMinTable

Step-by-step explanation

Step 1: EVALUATE
EVALUATE tells DAX that we want to return the result of a table expression.

Step 2: MaxMinTable
MaxMinTable is the table used in this example. Returning the table first allows us to inspect the values available in Column A and Column B.

What will you get?

The result displays the rows from MaxMinTable, including the values of Column A and Column B.

The values above are only for illustration. Your actual result depends on the data in MaxMinTable.

2. Finding the Minimum Result of an Expression

Query

EVALUATE
    ROW(
        "Min Difference", MINX(MaxMinTable, [Column A] + [Column B])
    )

Step-by-step explanation

Step 1: EVALUATE
EVALUATE returns the result of the table expression.

Step 2: ROW
ROW creates a single-row table. In this query, we use it to return one calculated result with the name Min Difference.

Step 3: “Min Difference”
This is the name assigned to the output column. It describes the result that we are calculating.

Step 4: MINX(MaxMinTable, …)
MINX iterates through every row of MaxMinTable.

Step 5: [Column A] + [Column B]
For each row, DAX adds the value from Column A to the value from Column B. MINX then compares all of these calculated results and returns the smallest one.

How MINX evaluates the expression

Suppose the table contains the following values:

MINX evaluates the expression [Column A] + [Column B] for each row and obtains 30, 35, and 23.

It then returns the smallest result, which is 23.

What will you get?

Understanding the Difference Between MIN and MINX

One important concept is the difference between MIN and MINX.

For example, if you only want the smallest value in Column A, you can use:

EVALUATE
    ROW(
        "Minimum Column A", MIN(MaxMinTable[Column A])
    )

But if you want to calculate an expression such as Column A + Column B for every row and then find the smallest result, MINX is appropriate.

EVALUATE
    ROW(
        "Min Difference", MINX(MaxMinTable, [Column A] + [Column B])
    )

Why Is MINX Useful?

MINX becomes useful when the value you want to minimize is not stored directly in a single column.

For example, you can use MINX when the calculation involves:

• Adding multiple columns.
• Subtracting one value from another.
• Calculating a price after applying a discount.
• Calculating a cost or margin for each row.
• Evaluating a more complex row-level expression.

EVALUATE
    ROW(
        "Minimum Value", MINX(MaxMinTable, [Column A] + [Column B])
    )

Important Notes

1. MINX is an iterator

MINX processes the table row by row and evaluates the expression in the context of each row.

2. The expression can involve multiple columns

The expression passed to MINX does not have to be a single column. In this example, we use [Column A] + [Column B].

3. MINX returns one scalar value

Although MINX iterates over a table, the final result is a single minimum value.

4. ROW converts the result into a table output

Because a DAX query using EVALUATE must return a table expression, ROW is used here to return the calculated scalar value as a one-row, one-column table.

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