I386LINUX/util/I386LINUX/doc/postgresql/html/dml-delete.html

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  96 >6.3. Deleting Data</A
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 105 >   So far we have explained how to add data to tables and how to
 106    change data.  What remains is to discuss how to remove data that is
 107    no longer needed.  Just as adding data is only possible in whole
 108    rows, you can only remove entire rows from a table.  In the
 109    previous section we discussed that SQL does not provide a way to
 110    directly address individual rows.  Therefore, removing rows can
 111    only be done by specifying conditions that the rows to be removed
 112    have to match.  If you have a primary key in the table then you can
 113    specify the exact row.  But you can also remove groups of rows
 114    matching a condition, or you can remove all rows in the table at
 115    once.
 116   </P
 117 ><P
 118 >   You use the <TT
 119 CLASS="LITERAL"
 120 >DELETE</TT
 121 > command to remove rows; the
 122    syntax is very similar to the <TT
 123 CLASS="LITERAL"
 124 >UPDATE</TT
 125 > command.
 126    For instance, to remove all rows from the products table that have a price of 10, use
 127 </P><PRE
 128 CLASS="PROGRAMLISTING"
 129 >DELETE FROM products WHERE price = 10;</PRE
 130 ><P>
 131   </P
 132 ><P
 133 >   If you simply write
 134 </P><PRE
 135 CLASS="PROGRAMLISTING"
 136 >DELETE FROM products;</PRE
 137 ><P>
 138    then all rows in the table will be deleted!  Caveat programmer.
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