Titlebook: Beginning Oracle SQL for Oracle Database 18c; From Novice to Profe Ben Brumm Book 2019 Ben Brumm 2019 Live SQL.Queries.Query.Structured Que

猛然一拉

Selecting Specific ColumnsIn this chapter, you’ll learn how to show specific columns from your table. It is not always necessary or desirable to return all columns as we did in Chapter .. As you’ll recall, we executed the following query in that chapter:...

dyspareunia

Restricting the ResultsWe have just learned how to display certain columns from a table. In this chapter, we’ll look at how to display certain rows from a table.

dendrites

Comparing DataYou’ve just learned how to restrict which rows you want to display, using a range of methods such as the equal to or greater than. Each of these methods checks a column against another value. This other value is checked using an “exact match.” The exact value that you specified is used to perform the check.

帶來

Applying Multiple FiltersIn the previous chapters, you’ve learned how to restrict the records you want to see. You looked at using symbols such as “equals to” and “greater than.” You also learned how to do partial matches using the . keyword and wildcard characters.

COMMA

Meander

Removing Duplicate ResultsWhen you store data in a table, as you have learned so far, you can just enter the values and save it. The data is then saved into the table. As long as the values you enter match the type of column, then it should work. This means you can’t enter a text value into a number column, for example.

火車車輪

DALLY

圖表證明

Foreknowledge

Understanding the Data TypesIn this chapter, you’ll learn what data types are, why you need them, and how the Oracle database handles different data types.