猛然一拉
发表于 2025-3-25 05:57:09
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
发表于 2025-3-25 08:34:59
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
发表于 2025-3-25 12:33:05
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.
带来
发表于 2025-3-25 16:19:13
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
发表于 2025-3-25 21:46:13
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Meander
发表于 2025-3-26 01:34:03
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.
火车车轮
发表于 2025-3-26 08:21:03
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DALLY
发表于 2025-3-26 09:49:30
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图表证明
发表于 2025-3-26 15:57:41
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Foreknowledge
发表于 2025-3-26 17:03:48
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.