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copied!<h2>Syntax:</h2> <pre><code>ALTER TABLE {TABLENAME} ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE} WITH VALUES </code></pre> <h2>Example:</h2> <pre><code>ALTER TABLE SomeTable ADD SomeCol Bit NULL --Or NOT NULL. CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated. DEFAULT (0)--Optional Default-Constraint. WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records. </code></pre> <h2>Notes:</h2> <p><strong>Optional Constraint Name:</strong><br /> If you leave out <code>CONSTRAINT D_SomeTable_SomeCol</code> then SQL Server will autogenerate<br />     a Default-Contraint with a funny Name like: <code>DF__SomeTa__SomeC__4FB7FEF6</code><br /></p> <p><strong>Optional With-Values Statement:</strong><br /> The <code>WITH VALUES</code> is only needed when your Column is Nullable<br />     and you want the Default Value used for Existing Records.<br /> If your Column is <code>NOT NULL</code>, then it will automatically use the Default Value<br />     for all Existing Records, whether you specify <code>WITH VALUES</code> or not.</p> <p><strong>How Inserts work with a Default-Constraint:</strong><br /> If you insert a Record into <code>SomeTable</code> and do <strong><em>not</em></strong> Specify <code>SomeCol</code>'s value, then it will Default to <code>0</code>.<br /> If you insert a Record <strong><em>and</em></strong> Specify <code>SomeCol</code>'s value as <code>NULL</code> (and your column allows nulls),<br />     then the Default-Constraint will <strong><em>not</em></strong> be used and <code>NULL</code> will be inserted as the Value.<br /></p> <p>Notes were based on everyone's great feedback below.<br /> Special Thanks to:<br />     @Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.</p>

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