MySQL ::: IF in INSERT INTO

INSERT INTO 
  [db1].[table] 
  ([column1][, [column2]])
SELECT 
  [columnA] AS [columnA][, [columnB] AS [column2]]
FROM [db2].[table] 
WHERE [columnC] IN ([num|'text'])

MySQL ::: INSERT from table

INSERT INTO 
    [table a]
    [([column1][,[column2]... ])]
SELECT 
    [columnA as column1],
    [columnB as column2]...
FROM 
    [table b]

MySQL ::: UPDATE from other table.

UPDATE 
  [a.table] a, 
  [b.table] b
SET 
  [a.column] = [b.column], 
  [[a.column] = [b.column]]
WHERE 
  [a.column] = [b.column]

MySQL ::: CASE use in UPDATE SQL

UPDATE [table] 
SET [column] = (
  SELECT 
    CASE [value] 

     WHEN [compare_value] THEN [result] 
      [WHEN [compare_value] THEN [result]] 

[ELSE [result]] 
    END)