SQL Operators
Table 2–1 lists the operators you can use in ESQL. These are the ANSI standard SQL operators, except as noted. These are also a subset of the operators available to the Progress 4GL. For more information on these operators, see the Progress SQL-89 Guide and Reference .
Table 2–1: Progress/SQL Operators SQL Operator Operation - (unary negative) Reverses the sign of a numeric expression. + (unary positive) Preserves the sign of a numeric expression. / (division) Divides one numeric expression by another to produce a decimal numeric result. * (multiplication) Multiplies two numeric expressions. - (DATE subtraction)1 Subtracts a number of days from a date to produce a DATE result, or subtracts one date from another to return the number of days between the two dates. - (subtraction) Subtracts one numeric expression from another. + (DATE addition)1 Adds a number of days to a date to produce a DATE result. + (concatenation) Concatenates two character strings or character expressions.1 + (addition) Adds two numeric expressions. < Returns a true value if the first of two expressions is less than the second.2 < = Returns a true value if the first of two expressions is less than or equal to the second.2 > Returns a true value if the first of two expressions is greater than the second.2 > = Returns a true value if the first of two expressions is greater than or equal to the second.2 = Returns a true value if two expressions are equal.2 < > Returns a true value if two expressions are not equal.2 NOT Reverses the true or false value of an expression. AND Returns a true value if each of two logical expressions is true. OR Returns a true value if either of two logical expressions is true.
NOTE: The SQL standard specifies that a NULL value in the result set of a subquery sets the truth value of the subquery relation to FALSE if the relation specifies that all values must satisfy the relational operator (if the relational operator is qualified by the ALL option). The subquery relation can yield an unknown (?) value if no other value satisfies the relational operator. For more information on the results of subquery relations, see the Progress SQL-89 Guide and Reference .
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