String Expressions

Both character strings in an operation (join, comparison) must have the same charset and sorting specified.

Joining Strings

Character strings may be joined using the concatenation operator ||. If one of the join operands is in UNICODE, then the result will be in UNICODE. If one character string has a charset and sorting specified then the resulting string will have the same charset and sorting. The resulting string will have the ignore case attribute if one of the operands has this attribute set. If one of the operands is a CLOB, or the joined string length exceeds the maximum string length, the result is a CLOB. Otherwise, the length of the result string is the sum of the lengths of both operands.

Binary strings may be joined using the concatenation operator ||. The join is always done for whole bytes. If one of the operands is a BLOB, or the joined string length exceeds the maximum string length, the result is a BLOB. Otherwise, the length of the result string is the sum of the lengths of both operands.

Comparing Strings

The operators >, <, =, <=, >= and <> can be used to compare character and binary string values. Case sensitivity will be ignored for character strings if one of the operands is not case sensitive. If one character string has a charset and sorting specified, this will be used for comparison. Otherwise, the comparison is done according to internal character code values.

Variations from the Intermediate to Entry level

The concatenation operator may not be used for bit conjunction in binary strings.

SQL properties defined by 602SQL implementation

The + operator (plus) may also be used as a concatenation operator.

Example:

IF res<>0 THEN  
  CALL Log_write('Mail initialization error number '||Int2str(res)); 
ELSE
...

Arithmetic Expressions

Expressions

Expressions with Date and Time