Hi all, a test with the gold data .... no errors on the load if i stop and restart the database errors is allways here. sql>select age,gender, count(*), avg(price) from car group by age, gender; +-----+-------+-------------+-----------------------+ | age |gender |count_gender |avg_price | +=====+=======+=============+=======================+ | 19 |f | 110025 | -1449.6788093615087 | | 41 |m | 97200 | -6411.6489300411522 | ........ 52 |f | 95940 | -6467.6865332499483 | +-----+-------+-------------+-----------------------+ Timer 2694.008 msec 92 rows sql>select count(*) from car where price = 0; +--------+ | count_ | +========+ | 0 | +--------+ Timer 2502.145 msec 1 rows sql>select count(*) from car where price < 0; +--------+ | count_ | +========+ | 0 | +--------+ Timer 148.724 msec 1 rows see the trace file . Regards Pierre -- Pierre Boizot Rue des philosophes , 13 1400 Yverdon les bains Mobile : +41 795713660