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Databases SQL Basics Finding the Data You Want Filtering on More than One Condition

reggaeshark
reggaeshark
8,542 Points

There should be a mention of using brackets for ordering.

in my opinion a key missing information

1 Answer

Steven Parker
Steven Parker
215,939 Points

If by "brackets" you mean "parentheses" (sometimes called "round brackets" in the UK), they are not necessary in simple expressions. Even in complex expressions they would typically only be used when it is necessary to change the default precedence of evaluation. This concept was probably considered beyond the scope of this introductory-level beginner course.

And what is the default precedence of evaluation?

Steven Parker
Steven Parker
215,939 Points

Precedence may vary slightly with other manufacturers, but for example here's the order for SQL Server:

  1. ~ (Bitwise NOT)
  2. * (Multiplication), / (Division), % (Modulus)
  3. + (Positive), - (Negative), + (Addition), + (Concatenation), - (Subtraction), & (Bitwise AND), ^ (Bitwise Exclusive OR), | (Bitwise OR)
  4. =, >, <, >=, <=, <>, !=, !>, !< (Comparison operators)
  5. NOT
  6. AND
  7. ALL, ANY, BETWEEN, IN, LIKE, OR, SOME
  8. = (Assignment)