chart.js data from mysql database showing no height on y- axis

i use chart.js to visualize data from mysql database, i read data from mysql database using php, i use json_encode to echo the results i want to display from the sql queries and then recieve it using ajax that all worked well for me but the problem is when i come to visualize the data i got no height for the y axis value for example if i have labels ("hi","hello","what") on the x axis coming from database and on y-axis i got values ("2.6","1.5","100") and also retrieved from the database i came with only output of three points on the x-axis regardless of the value of y-axis "i mean even the value 100 is on the x axis " and i have no lines connecting the three points but when i stop by the mouse on one of the points i got information about the point coordinates thnx in advance output result