Fordham, New York City's Jesuit University
back Back to course home page

SQL SELECT Statement
Quick Reference

The general form of a SQL SELECT statement is as follows:



select $\left[ \raisebox{-1ex}{\shortstack{\textbf{all}
\\ \textbf{distinct}}} \right]$ item [[as] alias] [, item [[as] alias] , ...]


[ into table ]


from table [alias] [, table [alias] , ...]


[ where predicate]


[ group by column [, column ...] [ having predicate] ]


[ order by column $\left[ \raisebox{-1ex}{\shortstack{\textbf{asc}
\\ \textbf{desc}}} \right]$ [, column $\left[ \raisebox{-1ex}{\shortstack{\textbf{asc}
\\ \textbf{desc}}} \right]$ ...] ]



NOTES:

  1. Keywords are shown in bold face. These must be typed as shown, but they may be in upper or lower case.

  2. Words shown in italics take on different values depending on the database scheme and the desired query.

  3. Elements [in brackets] are optional. An ellipsis (...) indicates any number of repetitions of the preceding optional element. Options listed in a vertical stack are mutually exclusive.

  4. The query may span multiple lines, and must be terminated by a semicolon in standard SQL92. (PostgreSQL allows \g in place of the semicolon.)

  5. In the select clause, an item can be the name of a table column or an expression involving various columns as well as constants. The alias is a name which will appear at the head of the column where the item is listed in the table produced in the query. These aliases may not be used in the predicate of a where or having clause, but may be used in an order by clause. The keyword as is optional in SQL92 but required before a column alias by PostgreSQL.

    The qualifier all specifies that duplicate rows, if any, should be retained in the result. This is the default. Use distinct to require duplicates to be eliminated. Standard SQL92 allows unique as a synonym for distinct, but PostgreSQL does not.

  6. The into clause creates a new table to receive the result of the query. The scheme of this table is defined by the items in the select clause.

  7. The from clause specifies tables to be searched for the query. If more than one table is listed, the Cartesian product is implied. An alias renames a table, usually for purposes of distinguishing different roles when the same table appears twice. These aliases may be used in the predicate of the where clause.

  8. The predicate of the where clause is any boolean expression involving columns of the tables as well as constants. Only rows satisfying the predicate will appear in the result.

  9. The group by clause is used when the select clause contains aggregate operators, to apply the operators to groups of rows having common values of the listed columns. The having subclause limits the results to groups satisfying its predicate. This predicate can only involve the grouping columns and aggregate operations applied to the other columns.

  10. The order by clause specifies the sorting of the results on the basis of the listed columns. The default order is asc (ascending). Use desc for descending order.


Robert Moniot 2004-03-03