Incorrect syntax near '=' error that I can't solve

Rich85
New Contributor

Hi,

I'm receiving the error Incorrect syntax near '=' when I run simple queries like the example below.  This only happens when I use a column created using a CASE statement in the WHERE clause.  I can use any other column in the WHERE clause, including the original columns used to create the new column, and the query runs fine.  

I'm sure this is a really simple one but it's escaping me at the minute.  Any help would be greatly appreciated

WITH isos AS
(
    SELECT DISTINCT
        Name,
        CAST(RecordingTime AS DATE) AS testDate,
        LOWER(TestType) AS testType,
        CASE
            WHEN LOWER(TestTypeName) = 'slppf' OR LOWER(TestType) = 'rsaip' THEN 'ankle iso push'  
            WHEN LOWER(TestTypeName) = 'slsquat' OR LOWER(TestType) = 'rskip' THEN 'knee iso push'
            WHEN LOWER(TestTypeName) = 'slhipext' OR LOWER(TestType) = 'rship' THEN 'hip iso push'
            ELSE LOWER(TestTypeName)
                    END AS testTypeName,
        `Peak Vertical Force / BW` AS peakVerticalForce
    FROM
        my_table
)

    SELECT *
    FROM isos
    WHERE testTypeName = 'hip iso push'