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From: Marcos Pegoraro <marcos@f10.com.br>
Date: Tue, 17 Mar 2026 17:54:45 -0300
Message-ID: <CAB-JLwYF8hWyAqVm3d8suG5PS9ZOJi53Y9tYtnvWxTsfOQzsrg@mail.gmail.com>
Subject: Re: Trying to understand pg_get_expr()
To: Adrian Klaver <adrian.klaver@aklaver.com>
Cc: pgsql-general <pgsql-general@postgresql.org>
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Em ter., 17 de mar. de 2026 =C3=A0s 17:36, Adrian Klaver <
adrian.klaver@aklaver.com> escreveu:

> Why is the second case not?:
>
I don't know, but you can see that it's not only for integers

CREATE TABLE default_test (
     id integer,
     fld_1 varchar DEFAULT 'test',
     fld_2 integer DEFAULT 0,
     fld_3 date DEFAULT Current_Date,
     fld_4 timestamp DEFAULT Current_Timestamp,
     fld_5 text DEFAULT 'x',
     fld_6 boolean DEFAULT 'on',
     fld_7 int4range DEFAULT '[1,2)',
     fld_8 char DEFAULT '1'
);

SELECT
     atttypid::regtype,
     pg_get_expr(adbin, adrelid)
FROM pg_class c inner join
     pg_attribute a on c.oid =3D attrelid
  inner join pg_attrdef d on c.oid =3D d.adrelid and adnum =3D attnum
WHERE
     relname =3D 'default_test' and attnum > 0;

regards
Marcs

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<div dir=3D"ltr"><div dir=3D"ltr"><div>Em ter., 17 de mar. de 2026 =C3=A0s =
17:36, Adrian Klaver &lt;<a href=3D"mailto:adrian.klaver@aklaver.com">adria=
n.klaver@aklaver.com</a>&gt; escreveu:</div></div><div class=3D"gmail_quote=
 gmail_quote_container"><blockquote class=3D"gmail_quote" style=3D"margin:0=
px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Why is the second case not?:<br></blockquote><div><span class=3D"gmail_defa=
ult" style=3D"font-family:verdana,sans-serif;color:rgb(102,102,102)">I don&=
#39;t know, but you can see that it&#39;s not only for integers</span>=C2=
=A0</div><div><br></div><div><div class=3D"gmail_default" style=3D""><font =
face=3D"verdana, sans-serif" style=3D"" color=3D"#666666">CREATE TABLE defa=
ult_test (</font></div><font face=3D"verdana, sans-serif" color=3D"#666666"=
>=C2=A0 =C2=A0 =C2=A0id integer,<br>=C2=A0 =C2=A0 =C2=A0fld_1 varchar DEFAU=
LT &#39;test&#39;,<br>=C2=A0 =C2=A0 =C2=A0fld_2 integer DEFAULT 0,<br>=C2=
=A0 =C2=A0 =C2=A0fld_3 date DEFAULT Current_Date,<br>=C2=A0 =C2=A0 =C2=A0fl=
d_4 timestamp DEFAULT Current_Timestamp,<br>=C2=A0 =C2=A0 =C2=A0fld_5 text =
DEFAULT &#39;x&#39;,<br>=C2=A0 =C2=A0 =C2=A0fld_6 boolean DEFAULT &#39;on&#=
39;,<br>=C2=A0 =C2=A0 =C2=A0fld_7 int4range DEFAULT &#39;[1,2)&#39;,<br>=C2=
=A0 =C2=A0 =C2=A0fld_8 char DEFAULT &#39;1&#39;<br>);<br><br>SELECT<br>=C2=
=A0 =C2=A0 =C2=A0atttypid::regtype,<br>=C2=A0 =C2=A0 =C2=A0pg_get_expr(adbi=
n, adrelid)<br>FROM pg_class c inner join<br>=C2=A0 =C2=A0 =C2=A0pg_attribu=
te a on c.oid =3D attrelid<br>=C2=A0 inner join pg_attrdef d on c.oid =3D d=
.adrelid and adnum =3D attnum<br>WHERE<br>=C2=A0 =C2=A0 =C2=A0relname =3D &=
#39;default_test&#39; and attnum &gt; 0;</font></div><div><font face=3D"ver=
dana, sans-serif" color=3D"#666666"><br></font></div><div><font face=3D"ver=
dana, sans-serif" color=3D"#666666">r<span class=3D"gmail_default" style=3D=
"font-family:verdana,sans-serif;color:rgb(102,102,102)">egards</span></font=
></div><div><font face=3D"verdana, sans-serif" color=3D"#666666"><span clas=
s=3D"gmail_default" style=3D"font-family:verdana,sans-serif;color:rgb(102,1=
02,102)">Marcs</span></font></div></div></div>

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