Gantt Matrix - How do I show multiple project phases in a single row and color format each phase?

Thanks for the reply from bhanu_gautam , please allow me to provide another insight:

Hi, danny_b 
Thanks for reaching out to the Microsoft fabric community forum.

My idea is similar to bhanu_gautam's.Regarding the issue you raised, my solution is as follows:

1.First, I created the following calculated table to serve as the columns of the matrix:

Fiscal Calendar = 
CALENDAR (
    MINX (
        {
            MIN ( 'New Project Table'[First Date] ),
            MIN ( 'New Project Table'[Last Date] )
        },
        [Value]
    ),
    MAXX (
        {
            MAX ( 'New Project Table'[First Date] ),
            MAX ( 'New Project Table'[Last Date] )
        },
        [Value]
    )
)

2.Next, I used the following measures as the values of the matrix:

Measure = 
VAR market1m =
    CALCULATE (
        MIN ( 'New Project Table'[First Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "Market"
        )
    )
VAR market2m =
    CALCULATE (
        MAX ( 'New Project Table'[Last Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "Market"
        )
    )
VAR Pilot1m =
    CALCULATE (
        MIN ( 'New Project Table'[First Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "Pilot"
        )
    )
VAR Pilot2m =
    CALCULATE (
        MAX ( 'New Project Table'[Last Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "Pilot"
        )
    )
VAR National1m =
    CALCULATE (
        MIN ( 'New Project Table'[First Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "National"
        )
    )
VAR National2m =
    CALCULATE (
        MAX ( 'New Project Table'[Last Date] ),
        FILTER (
            ALLEXCEPT ( 'New Project Table', 'New Project Table'[Project] ),
            'New Project Table'[Phase] = "National"
        )
    )
RETURN
    SWITCH (
        TRUE (),
        MAX ( 'Fiscal Calendar'[Date] ) >= market1m
            && MAX ( 'Fiscal Calendar'[Date] ) <= market2m, "#FF0000",
        
        MAX ( 'Fiscal Calendar'[Date] ) >= Pilot1m
            && MAX ( 'Fiscal Calendar'[Date] ) <= Pilot2m, "#00FF00",
        
        MAX ( 'Fiscal Calendar'[Date] ) >= National1m
            && MAX ( 'Fiscal Calendar'[Date] ) <= National2m, "#0000FF",
        
        "#FFFFFF" 
    )

3.Then, I modified the background colour:

4.Here's my final result, which I hope meets your requirements.

5.You may need to note that the matrix's column display has a 100-row limit. For more details, please refer to the documentation:

Solved: Missing Columns in Matrix - Microsoft Fabric Community

Please find the attached pbix relevant to the case.

Best Regards,

Leroy Lu