Difference between revisions of "Portable SQL/Common/Aliases"
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== Aliasing tables == | == Aliasing tables == | ||
Revision as of 18:52, 6 May 2007
Aliasing tables
Don't use the keyword "AS" between the table name and alias as no DBMS requires it and some don't recognize it. Instead, always write:
SELECT * FROM table t WHERE t.id = 0
Aliasing columns
Contrary to "Aliasing tables" the keyword "AS" between column name and alias is required by most database servers and should always be present:
SELECT count(*) AS cnt FROM table
Aliases for computed columns
The naming of computed columns implemented by the database servers is very different. Some name it like the computational expression ('count(*)'), most often in upper case and sometimes it isn't named at all. Therefore computed columns should be always given a name:
SELECT MAX(id) AS maxid FROM table
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