Specifying Criteria with the WHERE Clause
Note
Recall from Day 3 that the WHERE clause simply causes your queries to be more selective by limiting the amount of rows returned in the output.
Using just SELECT and FROM, you are limited to returning every row in a table. For example, using these two key words on the CHECKS table, you get all seven rows:
SQL> SELECT * 2 FROM CHECKS; CHECK# PAYEE AMOUNT REMARKS --------- -------------------- --------- ------------------- 1 MA BELL 150 HAVE SONS NEXT TIME 2 READING R.R. 245.34 TRAIN TO CHICAGO 3 MA BELL 200.32 CELLULAR PHONE 4 LOCAL UTILITIES 98 GAS 5 JOES STALE $ DENT 150 GROCERIES 16 CASH 25 WILD NIGHT OUT 17 JOANS GAS 25.1 GAS 7 rows selected.
With WHERE in your vocabulary, you can be more selective. ...
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