published solutions

README.md

@@ -1,10 +1,10 @@
 # How_to_retrieve_data_from_two_or_more_tables
 
-###Exercise 1
+### Exercise 1
 
 Write a SELECT statement that returns all columns from the Vendors table inner-joined with all columns from the Invoices table. This should return 114 rows. Hint: You can use an asterisk (*) to select the columns from both tables.
 
-###Exercise 2
+### Exercise 2
 
 Write a SELECT statement that returns these four columns:
 
@@ -19,7 +19,7 @@ Return one row for each invoice with a non-zero balance. This should return 11 r
 
 Sort the result set by vendor_name in ascending order.
 
-###Exercise 3
+### Exercise 3
 
 Write a SELECT statement that returns these three columns: 
 
@@ -31,7 +31,7 @@ Return one row for each vendor. This should return 122 rows.
 
 Sort the result set by account_description and then by vendor_name.
 
-###Exercise 4
+### Exercise 4
 
 Write a SELECT statement that returns these five columns: 
 
@@ -45,7 +45,7 @@ Use aliases for the tables. This should return 118 rows.
 
 Sort the final result set by vendor_name, invoice_date, invoice_number, and invoice_sequence.
 
-###Exercise 5
+### Exercise 5
 
 Write a SELECT statement that returns three columns: 
 
@@ -59,7 +59,7 @@ Return one row for each vendor whose contact has the same last name as another v
 
 Sort the result set by vendor_contact_last_name.
 
-###Exercise 6
+### Exercise 6
 
 Write a SELECT statement that returns these three columns:
 
@@ -75,7 +75,7 @@ Remove the invoice_id column from the SELECT clause.
 
 Sort the final result set by the account_number column.
 
-###Exercise 7
+###E xercise 7
 
 Use the UNION operator to generate a result set consisting of two columns from the Vendors table: vendor_name and vendor_state.
 

exercise-1.sql

@@ -0,0 +1,4 @@
+SELECT *
+FROM vendors JOIN invoices
+  ON vendors.vendor_id = invoices.vendor_id
+  

exercise-2.sql

@@ -0,0 +1,6 @@
+SELECT vendor_name, invoice_number, invoice_date,
+       invoice_total - payment_total - credit_total AS balance_due
+FROM vendors v JOIN invoices i
+  ON v.vendor_id = i.vendor_id
+WHERE invoice_total - payment_total - credit_total <> 0
+ORDER BY vendor_name

exercise-3.sql

@@ -0,0 +1,5 @@
+SELECT vendor_name, default_account_number AS default_account, 
+       account_description AS description
+FROM vendors v JOIN general_ledger_accounts gl
+  ON v.default_account_number = gl.account_number
+ORDER BY account_description, vendor_name

exercise-4.sql

@@ -0,0 +1,8 @@
+SELECT vendor_name, invoice_date, invoice_number, 
+       invoice_sequence AS li_sequence,
+       line_item_amount AS li_amount
+FROM vendors v JOIN invoices i
+  ON v.vendor_id = i.vendor_id
+ JOIN invoice_line_items li
+   ON i.invoice_id = li.invoice_id
+ORDER BY vendor_name, invoice_date, invoice_number, invoice_sequence

exercise-5.sql

@@ -0,0 +1,7 @@
+SELECT v1.vendor_id, 
+       v1.vendor_name,
+       CONCAT(v1.vendor_contact_first_name, ' ', v1.vendor_contact_last_name) AS contact_name
+FROM vendors v1 JOIN vendors v2
+    ON v1.vendor_id <> v2.vendor_id AND
+       v1.vendor_contact_last_name = v2.vendor_contact_last_name  
+ORDER BY v1.vendor_contact_last_name

exercise-6.sql

@@ -0,0 +1,5 @@
+SELECT gl.account_number, account_description, invoice_id
+FROM general_ledger_accounts gl LEFT JOIN invoice_line_items li
+  ON gl.account_number = li.account_number
+WHERE li.invoice_id IS NULL
+ORDER BY gl.account_number

exercise-7.sql

@@ -0,0 +1,8 @@
+  SELECT vendor_name, vendor_state
+  FROM vendors
+  WHERE vendor_state = 'CA'
+UNION
+  SELECT vendor_name, 'Outside CA'
+  FROM vendors
+  WHERE vendor_state <> 'CA'
+ORDER BY vendor_name