How to find rows that contain, or don’t contain, a value from a list. The list may be written in the query, or stored in a table.
SELECT rows from table A that have, or don’t have, a match in table B. While doing this, we’ll keep performance in mind.
How to get the length of the longest text in a column. Including Db2 specific syntax.
GROUP BY allows us to group identical values to aggregate data. What is not obvious is that it can be easily used to group values that belong to the same range, as well.
Most tables are created with a unique, progressive ID. But how to create an ID whose values are unique across multiple tables? For example, if value 1 is in table A, it must not be in table B.
How to select invalid email addresses from a column. How to reject attempts to insert invalid emails into a column.
How to get statistical data from a column in standard SQL. In particular it shows how to get the minimum, maximum, average values, and the standard deviation.
How to use the special SQL syntax to select rows with values in a given range, or outside of it. How to deal with bounds in a reversed order.
How to count a table rows, a table distinct rows, a column values, missing values, etc.