and { eq { max { all_rows ; yield ( megatons ) } ; 50 } ; eq { hop { argmax { all_rows ; yield ( megatons ) } ; date ( gmt ) } ; october 30 , 1961 } } = true
the maximum yield  megatons  record of all rows is 50 . the date  gmt  record of the row with superlative yield  megatons  record is october 30 , 1961 .