> On Sep 5, 2019, at 7:32 AM, Rob Sargent <robjsargent@xxxxxxxxx> wrote: > > > >> On Sep 4, 2019, at 9:14 PM, Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote: >> >>> On 9/4/19 5:23 PM, Rob Sargent wrote: >>> I've found the description of floating point types (here <https://www.postgresql.org/docs/10/datatype-numeric.html#DATATYPE-FLOAT>), but I'm looking for the rationale of the output format, particularly with respect to total digits presented (variable in a single select's output) and the dropping of a trailing zero (to some implying a loss of precision). Is the code my only guide here? >> >> Some examples would help explain your concerns. >> >> Bottom line, if you want precision use numeric. >> >> >> > When at my desk I’ll give example. Actual precision is not the issue. Purely cosmetics. Below I show a floating point column from a recent query. Here's my guess at what's happening in the formatting: 1) scientific notation if smaller than 1.0e-04 (I’m not in the very-much-larger-than-one world) 2) 15 digits after the most signicant 0 3) remove trailing zeros I may be alone in this but I find the presentation messy and that's unusual in the PostgreSQL world. To me the most agregious is the truncation of the zeros. Pick a number of digits and stick with it. One format too. 1 | 8.8999911000089e-05 | 2 | 0.00010999989000011 | 3 | 0.00011999988000012 | 4 | 0.000128999871000129 | 5 | 0.000132499966875008 | 6 | 0.000132999867000133 | 7 | 0.000136922971597714 | 8 | 0.000139499930250035 | 9 | 0.000158809516247166 | 10 | 0.000170294107629758 | 11 | 0.00028999971000029 | 12 | 0.000327999672000328 | 13 | 0.000628999371000629 | 14 | 0.00065999934000066 | 15 | 0.000667999332000668 | 16 | 0.000681999318000682 | 17 | 0.000683999316000684 | 18 | 0.000708999291000709 | 19 | 0.000722999277000723 | 20 | 0.000730999269000731 | 21 | 0.00074999925000075 | 22 | 0.000753999246000754 | 23 | 0.000755999244000756 | 24 | 0.000762999237000763 | 25 | 0.000765999234000766 | 26 | 0.000773999226000774 | 27 | 0.000780999219000781 | 28 | 0.000785999214000786 | 29 | 0.000787999212000788 | 30 | 0.000791999208000792 | 31 | 0.000793999206000794 | 32 | 0.000813999186000814 | 33 | 0.000817999182000818 | 34 | 0.000826999173000827 | 35 | 0.000833999166000834 | 36 | 0.000834999165000835 | 37 | 0.000838999161000839 | 38 | 0.000847999152000848 | 39 | 0.000854999145000855 | 40 | 0.000855999144000856 | 41 | 0.000857999142000858 | 42 | 0.00085999914000086 | 43 | 0.000864999135000865 | 44 | 0.00086999913000087 | 45 | 0.000875999124000876 | 46 | 0.000882999117000883 | 47 | 0.000887999112000888 | 48 | 0.000887999112000888 | 49 | 0.000904999095000905 | 50 | 0.000910999089000911 | 51 | 0.000912999087000913 | 52 | 0.000912999087000913 | 53 | 0.000914999085000915 | 54 | 0.000921999078000922 | 55 | 0.000922999077000923 | 56 | 0.000938999061000939 | 57 | 0.00094999905000095 | 58 | 0.000967999032000968 | 59 | 0.000971999028000972 | 60 | 0.000982999017000983 | 61 | 0.000995999004000996 | 62 | 0.001000998999001 | 63 | 0.001003998996001 | 64 | 0.001003998996001 | 65 | 0.00101099898900101 | 66 | 0.00101199898800101 | 67 | 0.00101599898400102 | 68 | 0.00101899898100102 | 69 | 0.00102199897800102 | 70 | 0.00102599897400103 | 71 | 0.00103099896900103 | 72 | 0.00104999895000105 | 73 | 0.00106899893100107 | 74 | 0.00107499892500108 | 75 | 0.00107599892400108 | 76 | 0.00108499891500109 | 77 | 0.00108699891300109 | 78 | 0.00108799891200109 | 79 | 0.0011039988960011 | 80 | 0.00110799889200111 | 81 | 0.00111099888900111 | 82 | 0.00111299888700111 | 83 | 0.00111599888400112 | 84 | 0.00111699888300112 | 85 | 0.00111999888000112 | 86 | 0.00111999888000112 | 87 | 0.00112099887900112 | 88 | 0.00116599883400117 | 89 | 0.00117461448106578 | 90 | 0.0011788180746529 | 91 | 0.00118099881900118 | 92 | 0.0011839994080003 | 93 | 0.00118827261924794 | 94 | 0.00118899881100119 | 95 | 0.0012049987950012 | 96 | 0.00120622217754733 | 97 | 0.00120999879000121 | 98 | 0.00121409079871902 | 99 | 0.00121481807138018 | 100 | 0.00122618178102479 | 101 | 0.00122699877300123 | 102 | 0.00122899877100123 | 103 | 0.00123999876000124 | 104 | 0.00125999874000126 | 105 | 0.00127766866245761 | 106 | 0.00128099935950032 | 107 | 0.00129099870900129 | 108 | 0.00129199870800129 | 109 | 0.00129299870700129 | 110 | 0.00129924967518758 | 111 | 0.0013019986980013 | 112 | 0.0013019986980013 | 113 | 0.00130449934775033 | 114 | 0.00133099866900133 | 115 | 0.00133106666886731 | 116 | 0.00135249932375034 | 117 | 0.00137999988500001 | 118 | 0.00142799857200143 | 119 | 0.00143799856200144 | 120 | 0.00144399855600144 | 121 | 0.0014563623123979 | 122 | 0.00146199853800146 | 123 | 0.00148299851700148 | 124 | 0.0014969985030015 | 125 | 0.00151499848500151 | 126 | 0.00151599848400152 | 127 | 0.00154699845300155 | 128 | 0.00154809076835538 | 129 | 0.00156599843400157 | 130 | 0.00156999843000157 | 131 | 0.00157899842100158 | 132 | 0.00163499836500163 | 133 | 0.00165199834800165 | 134 | 0.00165299917350041 | 135 | 0.00167799832200168 | 136 | 0.00168699831300169 | 137 | 0.00171599914200043 | 138 | 0.00172849913575043 | 139 | 0.00174599825400175 | 140 | 0.00199399800600199 | 141 | 0.0028989971010029 | 142 | 0.00417999582000418 | 143 | 0.00436199563800436 |
