DECIMAL datatype behavior while doing calculations in Teradata

Scenario: Look at the following result we get in Teradata. when multiplying two decimal the result data has double decimal precision

SELECT TYPE(CAST (2.3 AS DECIMAL(18,4)) * CAST (2.3 AS DECIMAL(18,4))  )\n

The result is:

DECIMAL(18,8)\n

• Teradata's basic rules are:\nWhen you add / substract / divide DECIMALs the resulting fractional precision is the greater of both operands, e.g. dec(10,2) + dec(10,4) = dec(xx,4)
  
• But when you multiply the fractional digits are added, e.g.dec(10,2) * dec(10,4) = dec(xx,6)
  
• And then there's the most important rule, people tend to forget:\nAfter each calculation the result is rounded to this precision

Example:

sel 2.0/3.00 * 100, 100*2.0/3.00;\n\n    *** Query completed. One row found. 2 columns returned.\n    *** Total elapsed time was 1 second.\n\n ((2.0/3.00)*100)   ((100*2.0)/3.00)\n-----------------  -----------------\n            67.00              66.67\n

nVector

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