How to remove the shadow of echarts bar chart mouse hover?

echart bar chart, when the mouse moves up, there will be a shadow next to the column, how to remove it.

Mar.20,2021

tooltip: {
    // ...,
    axisPointer: {
        type: ''
    }
}
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e4749e-44c2c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e4749e-44c2c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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