Select (SQL) Guide, Meaning , Facts, Information and Description
A
SELECT statement in
SQL returns a
result set of records from one of more tables.
Examples
| Table "T"
| Query
| Result
|
|
| SELECT * FROM T;
|
|
|
| SELECT C1 FROM T;
|
|
|
| SELECT * FROM T WHERE C1 = 1;
|
|
Given a table T, the
query SELECT * FROM T; will result in all the elements of all the rows of the table being shown.
With the same table, the query SELECT C1 FROM T; will result in the elements from the column C1 of all the rows of the table being shown — in Relational algebra terms, a projection will be performed.
With the same table, the query SELECT * FROM T WHERE C1 = 1; will result in all the elements of all the rows where the value of column C1 is '1' being shown — in Relational algebra terms, a selection will be performed, because of the WHERE keyword.
See also
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