diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 151a49037e4..52b5deb9873 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -952,6 +952,11 @@ SELECT '52093.89'::money::numeric::float8; + Division of a money value by an integer value is performed + with truncation of the fractional part towards zero. To get a rounded + result, divide by a floating-point value, or cast the money + value to numeric before dividing and back to money + afterwards. (The latter is preferable to avoid risking precision loss.) When a money value is divided by another money value, the result is double precision (i.e., a pure number, not money); the currency units cancel each other out in the division. diff --git a/src/backend/utils/adt/cash.c b/src/backend/utils/adt/cash.c index 82551c5f30e..2630c8ee867 100644 --- a/src/backend/utils/adt/cash.c +++ b/src/backend/utils/adt/cash.c @@ -623,7 +623,7 @@ cash_mul_flt8(PG_FUNCTION_ARGS) float8 f = PG_GETARG_FLOAT8(1); Cash result; - result = c * f; + result = rint(c * f); PG_RETURN_CASH(result); } @@ -638,7 +638,7 @@ flt8_mul_cash(PG_FUNCTION_ARGS) Cash c = PG_GETARG_CASH(1); Cash result; - result = f * c; + result = rint(f * c); PG_RETURN_CASH(result); } @@ -673,7 +673,7 @@ cash_mul_flt4(PG_FUNCTION_ARGS) float4 f = PG_GETARG_FLOAT4(1); Cash result; - result = c * f; + result = rint(c * (float8) f); PG_RETURN_CASH(result); } @@ -688,7 +688,7 @@ flt4_mul_cash(PG_FUNCTION_ARGS) Cash c = PG_GETARG_CASH(1); Cash result; - result = f * c; + result = rint((float8) f * c); PG_RETURN_CASH(result); } @@ -709,7 +709,7 @@ cash_div_flt4(PG_FUNCTION_ARGS) (errcode(ERRCODE_DIVISION_BY_ZERO), errmsg("division by zero"))); - result = rint(c / f); + result = rint(c / (float8) f); PG_RETURN_CASH(result); } @@ -758,7 +758,7 @@ cash_div_int8(PG_FUNCTION_ARGS) (errcode(ERRCODE_DIVISION_BY_ZERO), errmsg("division by zero"))); - result = rint(c / i); + result = c / i; PG_RETURN_CASH(result); } @@ -810,7 +810,7 @@ cash_div_int4(PG_FUNCTION_ARGS) (errcode(ERRCODE_DIVISION_BY_ZERO), errmsg("division by zero"))); - result = rint(c / i); + result = c / i; PG_RETURN_CASH(result); } @@ -860,7 +860,7 @@ cash_div_int2(PG_FUNCTION_ARGS) (errcode(ERRCODE_DIVISION_BY_ZERO), errmsg("division by zero"))); - result = rint(c / s); + result = c / s; PG_RETURN_CASH(result); } diff --git a/src/test/regress/expected/money.out b/src/test/regress/expected/money.out index 538235c4cc2..efb48f1acd6 100644 --- a/src/test/regress/expected/money.out +++ b/src/test/regress/expected/money.out @@ -185,6 +185,44 @@ SELECT * FROM money_data; $123.46 (1 row) +-- rounding vs. truncation in division +SELECT '878.08'::money / 11::float8; + ?column? +---------- + $79.83 +(1 row) + +SELECT '878.08'::money / 11::float4; + ?column? +---------- + $79.83 +(1 row) + +SELECT '878.08'::money / 11::int; + ?column? +---------- + $79.82 +(1 row) + +SELECT '878.08'::money / 11::smallint; + ?column? +---------- + $79.82 +(1 row) + +-- check for precision loss in division +SELECT '90000000000000099.00'::money / 10::int; + ?column? +--------------------------- + $9,000,000,000,000,009.90 +(1 row) + +SELECT '90000000000000099.00'::money / 10::smallint; + ?column? +--------------------------- + $9,000,000,000,000,009.90 +(1 row) + -- Cast int4/int8 to money SELECT 1234567890::money; money diff --git a/src/test/regress/sql/money.sql b/src/test/regress/sql/money.sql index 09b9476b706..f0db5fa4322 100644 --- a/src/test/regress/sql/money.sql +++ b/src/test/regress/sql/money.sql @@ -57,6 +57,16 @@ DELETE FROM money_data; INSERT INTO money_data VALUES ('$123.459'); SELECT * FROM money_data; +-- rounding vs. truncation in division +SELECT '878.08'::money / 11::float8; +SELECT '878.08'::money / 11::float4; +SELECT '878.08'::money / 11::int; +SELECT '878.08'::money / 11::smallint; + +-- check for precision loss in division +SELECT '90000000000000099.00'::money / 10::int; +SELECT '90000000000000099.00'::money / 10::smallint; + -- Cast int4/int8 to money SELECT 1234567890::money; SELECT 12345678901234567::money;