Date function:
<=                 
- CURRENT_DATE     
- CURRENT_TIME     
- CURRENT_TIMESTAMP
- DATE             
- DATEDIFF         
- DATE_ADD         
- DATE_SUBTRACT    
- DAYNAME          
- EXTRACT          
- LAST_DAY         
- MONTHNAME        
- TIME             
- TIMEDIFF         
- TIMESTAMPDIFF    
  YEAR             
  QUARTER          
  MONTH            
  WEEK             
  DAY              
  HOUR             
  MINUTE           
  SECOND           
  DAYOFWEEK        
  WEEKDAY          
  DAYOFYEAR