What does "+date+" mean in this context?
SELECT LTRIM(RTRIM(CONVERT(char(10), MAX(date), 101))) as str 
FROM   inventory 
WHERE  date &lt; '" + date + "'"



  Table: inventory  
  
  Field: date (Your inventory table has a field named date)


MAX(date): Returns the highest date according WHERE conditions.  

CONVERT(char(10), MAX(date), 101): Convert one data type into another applying some style. On this case 101 means U.S. format: mm/dd/yyyy. This is a MS SQL-Server specific syntax.

RTRIM(): Returns a character string after truncating all trailing spaces.

LTRIM(): Returns a character expression after it removes leading blanks.


Give me the highest date of inventory table, using mm/dd/yyyy format,
without leading and trailing spaces and considering only records
where this date is lower than an specific value.