CONCAT(string1, string2): Concatenates two string fields or literals. For example:

select x from Magazine x where concat(x.title, 's') = 'JDJs'

SUBSTRING(string, startIndex, length): Returns the part of the string argument starting at startIndex (1-based) and ending at length characters past startIndex.

select x from Magazine x where substring(x.title, 1, 1) = 'J'

TRIM([LEADING | TRAILING | BOTH] [character FROM] string: Trims the specified character from either the beginning (LEADING) end (TRAILING) or both ( BOTH) of the string argument. If no trim character is specified, the space character will be trimmed.

select x from Magazine x where trim(both 'J' from x.title) = 'D'

LOWER(string): Returns the lower-case of the specified string argument.

select x from Magazine x where lower(x.title) = 'jdj'

UPPER(string): Returns the upper-case of the specified string argument.

select x from Magazine x where upper(x.title) = 'JAVAPRO'

LENGTH(string): Returns the number of characters in the specified string argument.

select x from Magazine x where length(x.title) = 3

LOCATE(searchString, candidateString [, startIndex]): Returns the first index of searchString in candidateString. Positions are 1-based. If the string is not found, returns 0.

select x from Magazine x where locate('D', x.title) = 2

ABS(number): Returns the absolute value of the argument.

select x from Magazine x where abs(x.price) >= 5.00

SQRT(number): Returns the square root of the argument.

select x from Magazine x where sqrt(x.price) >= 1.00

MOD(number, divisor): Returns the modulo of number and divisor.

select x from Magazine x where mod(x.price, 10) = 0

CURRENT_DATE: Returns the current date.

CURRENT_TIME: Returns the current time.

CURRENT_TIMESTAMP: Returns the current timestamp.