Amazing! Now let's summarize what we've learned in this part:

• Computations using floating point numbers are not always exact. Use the decimal, numeric, or money data types for all money columns and whenever precision matters.
• Dividing two integers is integer division, which is not always accurate. Use CAST(column AS TYPE) or the :: operator to avoid it.
• Avoid division by zero.

We've learned some useful functions:

• The modulo operation (x % y) returns the remainder of x by y division.
• ROUND(x, p) rounds x to the nearest integer or to the specified number of decimal digits (p).
• CEILING(x) rounds up to the nearest integer value.
• FLOOR(x) rounds down to the nearest integer value.
• ABS(x) returns the absolute value of x.
• TRUNC(x, p) – removes decimal digits given in p from the number x; TRUNC(x) removes all decimal digits.
• The :: operator and the CAST() function convert data types.

The queries we've written so far have been fairly simple. Let's test your knowledge with some more advanced exercises.