Correction to the initial article on "How to Remove Leading Zero" (#205)

* create-altering-student-table-MySQL-PostgreSQL

* Add files via upload

* Update altering-student-table-MySQL-PostgreSQL

* Update altering-student-table-SQL-Server.sql

* Update using-TRIM-with-SQL-Server.sql

* Rename using-TRIM-function-with-MySQL.sql to trimming-with-MySQL.sql

* Rename using-TRIM-with-PostgreSQL.sql to trimming-with-PostgreSQL.sql

* Rename using-TRIM-with-SQL-Server.sql to trimming-with-SQL-Server.sql

* Rename altering-student-table-MySQL-PostgreSQL to altering-student-table-MySQL-PostgreSQL.sql

Author: Latsan

sql-queries-5/removing-leading-zeros-in-sql/altering-student-table-MySQL-PostgreSQL.sql

@@ -0,0 +1,9 @@
+ALTER TABLE Student ADD COLUMN formatted_id VARCHAR(10);
+
+UPDATE Student 
+SET formatted_id = CONCAT('0', id) 
+WHERE id <= 2000;
+
+UPDATE Student 
+SET formatted_id = id 
+WHERE formatted_id IS NULL;

sql-queries-5/removing-leading-zeros-in-sql/altering-student-table-SQL-Server.sql

@@ -0,0 +1,12 @@
+-- Add a new column to the Student table 
+ALTER TABLE Student ADD formatted_id VARCHAR(10); 
+
+-- Update the new column with leading zeros 
+UPDATE Student 
+SET formatted_id = '0' + CAST(id AS VARCHAR(10))
+WHERE id <= 2000;
+
+-- Update remaining rows where formatted_id is NULL 
+UPDATE Student 
+SET formatted_id = CAST(id AS VARCHAR(10)) 
+WHERE formatted_id IS NULL;

sql-queries-5/removing-leading-zeros-in-sql/example-formatted-data.sql

@@ -0,0 +1,3 @@
+SELECT name, formatted_id 
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/trimming-with-MySQL.sql

@@ -0,0 +1,4 @@
+SELECT name, formatted_id,
+       TRIM(LEADING '0' FROM formatted_id) AS cleaned_id
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/trimming-with-PostgreSQL.sql

@@ -0,0 +1,4 @@
+SELECT name, formatted_id,
+       LTRIM(formatted_id, '0') AS cleaned_id
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/trimming-with-SQL-Server.sql

@@ -0,0 +1,7 @@
+SELECT name, formatted_id,
+       SUBSTRING(formatted_id, 
+                 PATINDEX('%[^0]%', formatted_id), 
+                 LEN(formatted_id)
+       ) AS cleaned_id
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/using-CAST-function-MySQL.sql

@@ -0,0 +1,4 @@
+SELECT name, formatted_id,
+       CAST(formatted_id AS UNSIGNED) AS cleaned_id
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/using-CAST-function-PostgreSQL.sql

@@ -0,0 +1,6 @@
+SELECT 
+	name, 
+    formatted_id, 
+    CAST(formatted_id AS INTEGER) AS cleaned_id 
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/using-CAST-function-SQL-Server.sql

@@ -0,0 +1,6 @@
+SELECT 
+	name, 
+    formatted_id, 
+    CAST(formatted_id AS INT) AS cleaned_id 
+FROM Student 
+WHERE id in (1607,1007,2017,1010,1111,2008);

sql-queries-5/removing-leading-zeros-in-sql/using-CONVERT-function-with-MySQL.sql

@@ -0,0 +1,6 @@
+SELECT 
+	name, 
+	formatted_id, 
+    CONVERT(formatted_id, UNSIGNED) AS cleaned_id 
+FROM Student 
+WHERE id IN (1607,1007,2017,1010,1111,2008);