Back in high school chemistry, I remember waiting with my bench partner for crystals to form on our stick in the cup of blue ...

Now we need to group adjacent records with the same value, extract the start time of this group and the start time of the next group as the start and end time of this group, and form a new ...

Below, we will use the example of orders and order details tables to compare the performance of esProc SPL and MySQL in calculating EXISTS and NOT EXISTS for primary-subtable joins.