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+====== Altering Tables ======
+===== Adding a column =====
+To add a column **if it does not exist** you can do a Prepare/Execute function as follows:
+<code sql>
+SET @dbname = DATABASE();
+SET @tablename = "tableName";
+SET @columnname = "colName";
+SET @preparedStatement = (SELECT IF(
+  (
+    SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+    WHERE
+      (table_name = @tablename)
+      AND (table_schema = @dbname)
+      AND (column_name = @columnname)
+  ) > 0,
+  "SELECT 1",
+  CONCAT("ALTER TABLE ", @tablename, " ADD ", @columnname, " INT(11);")
+));
+PREPARE alterIfNotExists FROM @preparedStatement;
+EXECUTE alterIfNotExists;
+DEALLOCATE PREPARE alterIfNotExists;
+</code>
+Other ways of doing this are available in the discussion at [[https://stackoverflow.com/questions/24571611/mysql-alter-table-if-column-not-exists]]
+===== Links =====
+  * [[https://stackoverflow.com/questions/24571611/mysql-alter-table-if-column-not-exists]]