Update fix-when-using-DELETE-statement.sql

Author: dvohra09

sql-queries-11/how-to-interpret-and-fix-the-MySQL-Error-1093/fix-when-using-DELETE-statement.sql

@@ -1 +1,41 @@
 
+-- This statement generates the Error 1093
+DELETE FROM Program
+WHERE id IN 
+(SELECT id FROM Program WHERE department_id=1);
+
+-- This statement fixes the Error 1093 in the preceding example using a derived table
+DELETE FROM Program
+WHERE id IN (
+  SELECT subquery_program.id
+  FROM (
+    SELECT id
+    FROM Program
+    WHERE department_id=1
+  ) AS subquery_program
+);
+
+
+-- This set of statements fixes the Error 1093 in the example using a temporary table
+-- Create a temporary table 
+CREATE TEMPORARY TABLE temp_ids AS
+SELECT id 
+FROM Program 
+WHERE department_id=1;
+
+-- Delete from the main table using the temporary table
+DELETE FROM Program
+WHERE id 
+IN (SELECT id FROM temp_ids);
+
+-- Drop the temporary table
+DROP TEMPORARY TABLE IF EXISTS temp_ids;
+
+-- This statement fixes the Error 1093 using a self-join
+DELETE t1
+FROM Program t1
+JOIN (
+    SELECT id
+    FROM Program
+    WHERE department_id=1
+) AS t2 ON t1.id = t2.id;