The following table provides the conditions when comparisons produce TRUE results.
For simplicity, assume the syntax:
expression_1— operator — expression_2
expression_1 and expression_2 must contain the same number of scalar values and range from 1 through n rows, represented by r, so that the rth components of expression_1 and expression_2 are expression_1r and expression_2r.
The δth item in the range is notated as row δ such that the δth component of expression_1 is notated as expression_1δ and the δth component of expression_2 is notated as expression_2δ.
The data types of expression_1 and expression_2 must be compatible. If the data types of the expressions differ, Teradata Database performs an implicit conversion from one type to another in some cases.
| This comparison … | Is TRUE if … |
|---|---|
| expression_1 = expression_2 | ∀ r, expression_1r = expression_2r is TRUE. |
| expression_1 <> expression_2 | ∃ δ such that expression_1δ <> expression_2δ is TRUE. |
| expression_1 < expression_2 | ∃ δ such that expression_1δ < expression_2δ is TRUE and for all r < δ, expression_1r = expression_2r is TRUE. |
| expression_1 > expression_2 | ∃ δ such that expression_1δ >expression_2δ is TRUE and for all r > δ, expression_1r = expression_2r is TRUE. |
| expression_1 <= expression_2 | expression_1 < expression_2 is TRUE or expression_1 = expression_2 is TRUE. |
| expression_1 => expression_2 | expression_1 > expression_2 is TRUE or expression_1 = expression_2 is TRUE. |