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Excel at using Excel with these keyboard hotkeys that will save you minutes of time—and hours of aggravation. The post 80 of the Most Useful Excel Shortcuts appeared first on Reader's Digest.
Using IIf, person.Name would be evaluated even if person is null (Nothing), causing an exception. With a true short-circuiting conditional operator, person.Name is not evaluated unless person is not null. Visual Basic Version 9 has added the operator If() in addition to the existing IIf() function that existed previously.
Most keyboard shortcuts require the user to press a single key or a sequence of keys one after the other. Other keyboard shortcuts require pressing and holding several keys simultaneously (indicated in the tables below by the + sign). Keyboard shortcuts may depend on the keyboard layout.
The Null marker indicates the absence of a value, and is distinct from a value of 0 for an integer column or an empty string for a text column. The concept of Nulls enforces the 3-valued-logic in SQL, which is a concrete implementation of the general 3-valued logic. [12]
COMMAND. ACTION. Ctrl/⌘ + C. Select/highlight the text you want to copy, and then press this key combo. Ctrl/⌘ + F. Opens a search box to find a specific word, phrase, or figure on the page
E. F. Codd mentioned nulls as a method of representing missing data in the relational model in a 1975 paper in the FDT Bulletin of ACM-SIGMOD.Codd's paper that is most commonly cited with the semantics of Null (as adopted in SQL) is his 1979 paper in the ACM Transactions on Database Systems, in which he also introduced his Relational Model/Tasmania, although much of the other proposals from ...
However, note that performance suffers when there are more than 100 alternatives. Placing common values earlier in the list of cases can cause the function to execute significantly faster. For each case, either side of the equals sign "=" can be a simple string, a call to a parser function (including #expr to evaulate expressions), or a ...
Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form: