On Tue, Sep 12, 2017 at 8:58 PM, boB Stepp <robertvst...@gmail.com> wrote: > On Tue, Sep 12, 2017 at 2:17 PM, Mats Wichmann <m...@wichmann.us> wrote: >> On 09/12/2017 01:05 PM, boB Stepp wrote: >>> As I continue to read about SQL, one thing jumps out: There are many >>> differences between how SQL statements are implemented among the >>> different database products. Even for relatively simple, >>> straightforward things like field concatenation. One DB might use >>> "||" as the operator. Another uses "+". Yet another only uses a >>> "CONCAT" function. This is crazy! > > [...] > >> But dealing with "local extension to SQL" is a different problem. SQL >> is actually a standard and should work the same everywhere, but then >> people decide they need to improve it. Being agnostic means avoiding >> mysql-specific syntax, postgres-specific syntax, etc. Which means you >> need to know what is specific in the first place... > > In the example I was alluding to, concatenating fields, surely this is > a "standard SQL" query? So, for instance, if I had a Sales table with > FirstName and LastName fields and wanted to use SQL to get the full > name from these: > > 1) In Microsoft SQL Server: > SELECT > FirstName + ' ' + LastName > FROM Sales > > 2) MySQL: > SELECT > CONCAT(FirstName, ' ', LastName) > FROM Sales; > > 3)SQLite: > SELECT > FirstName || ' ' || LastName > FROM Sales; > > And these would be the SQL commands/statements I would have > cursor.execute use from the sqlite3 module...
I misspoke somewhat here. I suppose there are different database wrappers to access different databases. But the standard python database api should still use a cursor.execute to run SQL commands no matter the wrapper? > ... They would be different > depending on which database product I was using. Am I horribly > misunderstanding something??? And if not, I have several other > apparently fundamental SQL examples where similar situations exist > based on the book on SQL I am only 43 pages into! > > -- > boB -- boB _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
