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func.sgml
资源名称：postgresql-6.5.2.tar.gz　[点击查看]
上传用户：blenddy
上传日期：2007-01-07
资源大小：6495k
文件大小：21k
源码类别：

数据库系统

开发平台：

Unix_Linux

func.sgml：源码内容
  1.  <chapter id="functions">
  2.   <title id="functions-title">Functions</title>
  4.   <abstract>
  5.    <para>
  6.     Describes the built-in functions available
  7.     in <productname>Postgres</productname>.
  8.    </para>
  9.   </abstract>
  11.   <para>
  12.    Many data types have functions available for conversion to other related types.
  13.    In addition, there are some type-specific functions. Some functions are also
  14.    available through operators and may be documented as operators only.
  15.   </para>
  17.   <sect1>
  18.    <title id="sql-funcs">SQL Functions</title>
  20.    <para>
  21.     <quote><acronym>SQL</acronym> functions</quote> are constructs
  22.     defined by the <acronym>SQL92</acronym> standard which have
  23.     function-like syntax but which can not be implemented as simple
  24.     functions. 
  25.    </para>
  27.    <para>
  28.     <table tocentry="1">
  29.      <title>SQL Functions</title>
  30.      <tgroup cols="4">
  31.       <thead>
  32.        <row>
  33. <entry>Function</entry>
  34. <entry>Returns</entry>
  35. <entry>Description</entry>
  36. <entry>Example</entry>
  37.        </row>
  38.       </thead>
  39.       <tbody>
  40.        <row>
  41. <entry> COALESCE(<replaceable class="parameter">list</replaceable>) </entry>
  42. <entry> non-NULL </entry>
  43. <entry> return first non-NULL value in list </entry>
  44. <entry> COALESCE(<replaceable class="parameter">r"</replaceable>le>, <replaceable
  45.   class="parameter">c2</replaceable> + 5, 0) </entry>
  46.        </row>
  47.        <row>
  48. <entry> IFNULL(<replaceable class="parameter">input</replaceable>,<replaceable class="parameter">non-NULL substitute</replaceable>) </entry>
  49. <entry> non-NULL </entry>
  50. <entry> return second argument if first is NULL </entry>
  51. <entry> IFNULL(<replaceable class="parameter">c1</replaceable>, 'N/A')</entry>
  52.        </row>
  53.        <row>
  54. <entry> CASE WHEN <replaceable class="parameter">expr</replaceable> THEN <replaceable class="parameter">expr</replaceable> [...] ELSE <replaceable class="parameter">expr</replaceable> END </entry>
  55. <entry> <replaceable class="parameter">expr</replaceable> </entry>
  56. <entry> return expression for first true clause </entry>
  57. <entry> CASE WHEN <replaceable class="parameter">c1</replaceable> = 1 THEN 'match' ELSE 'no match' END </entry>
  58.        </row>
  59.       </tbody>
  60.      </tgroup>
  61.     </table>
  62.    </para>
  63.   </sect1>
  65.   <sect1>
  66.    <title id="math-funcs">Mathematical Functions</title>
  68.    <para>
  69.     <table tocentry="1">
  70.      <title>Mathematical Functions</title>
  71.      <tgroup cols="4">
  72.       <thead>
  73.        <row>
  74. <entry>Function</entry>
  75. <entry>Returns</entry>
  76. <entry>Description</entry>
  77. <entry>Example</entry>
  78.        </row>
  79.       </thead>
  80.       <tbody>
  81.        <row>
  82. <entry> dexp(float8) </entry>
  83. <entry> float8 </entry>
  84. <entry> raise e to the specified exponent </entry>
  85. <entry> dexp(2.0) </entry>
  86.        </row>
  87.        <row>
  88. <entry> dpow(float8,float8) </entry>
  89. <entry> float8 </entry>
  90. <entry> raise a number to the specified exponent </entry>
  91. <entry> dpow(2.0, 16.0) </entry>
  92.        </row>
  93.        <row>
  94. <entry> float(int) </entry>
  95. <entry> float8 </entry>
  96. <entry> convert integer to floating point </entry>
  97. <entry> float(2) </entry>
  98.        </row>
  99.        <row>
  100. <entry> float4(int) </entry>
  101. <entry> float4 </entry>
  102. <entry> convert integer to floating point </entry>
  103. <entry> float4(2) </entry>
  104.        </row>
  105.        <row>
  106. <entry> integer(float) </entry>
  107. <entry> int </entry>
  108. <entry> convert floating point to integer </entry>
  109. <entry> integer(2.0) </entry>
  110.        </row>
  111.       </tbody>
  112.      </tgroup>
  113.     </table>
  114.    </para>
  115.   </sect1>
  117.   <sect1>
  118.    <title>String Functions</title>
  120.    <para>
  121.     SQL92 defines string functions with specific syntax. Some of these
  122.     are implemented using other <productname>Postgres</productname> functions.
  123.     The supported string types for <acronym>SQL92</acronym> are
  124.     <type>char</type>, <type>varchar</type>, and <type>text</type>.
  125.    </para>
  127.    <para>
  128.     <table tocentry="1">
  129.      <title><acronym>SQL92</acronym> String Functions</title>
  130.      <tgroup cols="4">
  131.       <thead>
  132.        <row>
  133. <entry>Function</entry>
  134. <entry>Returns</entry>
  135. <entry>Description</entry>
  136. <entry>Example</entry>
  137.        </row>
  138.       </thead>
  139.       <tbody>
  140.        <row>
  141. <entry> char_length(string) </entry>
  142. <entry> int4 </entry>
  143. <entry> length of string </entry>
  144. <entry> char_length('jose') </entry>
  145.        </row>
  146.        <row>
  147. <entry> character_length(string) </entry>
  148. <entry> int4 </entry>
  149. <entry> length of string </entry>
  150. <entry> char_length('jose') </entry>
  151.        </row>
  152.        <row>
  153. <entry> lower(string) </entry>
  154. <entry> string </entry>
  155. <entry> convert string to lower case </entry>
  156. <entry> lower('TOM') </entry>
  157.        </row>
  158.        <row>
  159. <entry> octet_length(string) </entry>
  160. <entry> int4 </entry>
  161. <entry> storage length of string </entry>
  162. <entry> octet_length('jose') </entry>
  163.        </row>
  164.        <row>
  165. <entry> position(string in string) </entry>
  166. <entry> int4 </entry>
  167. <entry> location of specified substring </entry>
  168. <entry> position('o' in 'Tom') </entry>
  169.        </row>
  170.        <row>
  171. <entry> substring(string [from int] [for int]) </entry>
  172. <entry> string </entry>
  173. <entry> extract specified substring </entry>
  174. <entry> substring('Tom' from 2 for 2) </entry>
  175.        </row>
  176.        <row>
  177. <entry> trim([leading|trailing|both] [string] from string) </entry>
  178. <entry> string </entry>
  179. <entry> trim characters from string </entry>
  180. <entry> trim(both 'x' from 'xTomx') </entry>
  181.        </row>
  182.        <row>
  183. <entry> upper(text) </entry>
  184. <entry> text </entry>
  185. <entry> convert text to upper case </entry>
  186. <entry> upper('tom') </entry>
  187.        </row>
  188.       </tbody>
  189.      </tgroup>
  190.     </table>
  191.    </para>
  193.    <para>
  194.     Many additional string functions are available for text, varchar(), and char() types.
  195.     Some are used internally to implement the SQL92 string functions listed above.
  196.    </para>
  198.    <para>
  199.     <table tocentry="1">
  200.      <title>String Functions</title>
  201.      <tgroup cols="4">
  202.       <thead>
  203.        <row>
  204. <entry>Function</entry>
  205. <entry>Returns</entry>
  206. <entry>Description</entry>
  207. <entry>Example</entry>
  208.        </row>
  209.       </thead>
  210.       <tbody>
  211.        <row>
  212. <entry> char(text) </entry>
  213. <entry> char </entry>
  214. <entry> convert text to char type </entry>
  215. <entry> char('text string') </entry>
  216.        </row>
  217.        <row>
  218. <entry> char(varchar) </entry>
  219. <entry> char </entry>
  220. <entry> convert varchar to char type </entry>
  221. <entry> char(varchar 'varchar string') </entry>
  222.        </row>
  223.        <row>
  224. <entry> initcap(text) </entry>
  225. <entry> text </entry>
  226. <entry> first letter of each word to upper case </entry>
  227. <entry> initcap('thomas') </entry>
  228.        </row>
  229.        <row>
  230. <entry> lpad(text,int,text) </entry>
  231. <entry> text </entry>
  232. <entry> left pad string to specified length </entry>
  233. <entry> lpad('hi',4,'??') </entry>
  234.        </row>
  235.        <row>
  236. <entry> ltrim(text,text) </entry>
  237. <entry> text </entry>
  238. <entry> left trim characters from text </entry>
  239. <entry> ltrim('xxxxtrim','x') </entry>
  240.        </row>
  241.        <row>
  242. <entry> textpos(text,text) </entry>
  243. <entry> text </entry>
  244. <entry> locate specified substring </entry>
  245. <entry> position('high','ig') </entry>
  246.        </row>
  247.        <row>
  248. <entry> rpad(text,int,text) </entry>
  249. <entry> text </entry>
  250. <entry> right pad string to specified length </entry>
  251. <entry> rpad('hi',4,'x') </entry>
  252.        </row>
  253.        <row>
  254. <entry> rtrim(text,text) </entry>
  255. <entry> text </entry>
  256. <entry> right trim characters from text </entry>
  257. <entry> rtrim('trimxxxx','x') </entry>
  258.        </row>
  259.        <row>
  260. <entry> substr(text,int[,int]) </entry>
  261. <entry> text </entry>
  262. <entry> extract specified substring </entry>
  263. <entry> substr('hi there',3,5) </entry>
  264.        </row>
  265.        <row>
  266. <entry> text(char) </entry>
  267. <entry> text </entry>
  268. <entry> convert char to text type </entry>
  269. <entry> text('char string') </entry>
  270.        </row>
  271.        <row>
  272. <entry> text(varchar) </entry>
  273. <entry> text </entry>
  274. <entry> convert varchar to text type </entry>
  275. <entry> text(varchar 'varchar string') </entry>
  276.        </row>
  277.        <row>
  278. <entry> translate(text,from,to) </entry>
  279. <entry> text </entry>
  280. <entry> convert character in string </entry>
  281. <entry> translate('12345', '1', 'a') </entry>
  282.        </row>
  283.        <row>
  284. <entry> varchar(char) </entry>
  285. <entry> varchar </entry>
  286. <entry> convert char to varchar type </entry>
  287. <entry> varchar('char string') </entry>
  288.        </row>
  289.        <row>
  290. <entry> varchar(text) </entry>
  291. <entry> varchar </entry>
  292. <entry> convert text to varchar type </entry>
  293. <entry> varchar('text string') </entry>
  294.        </row>
  295.       </tbody>
  296.      </tgroup>
  297.     </table>
  298.    </para>
  300.    <para>
  301.     Most functions explicitly defined for text will work for char() and varchar() arguments.
  302.    </para>
  303.   </sect1>
  305.   <sect1>
  306.    <title>Date/Time Functions</title>
  308.    <para>
  309.     The date/time functions provide a powerful set of tools
  310.     for manipulating various date/time types.
  311.    </para>
  313.    <para>
  314.     <table tocentry="1">
  315.      <title>Date/Time Functions</title>
  316.      <tgroup cols="4">
  317.       <thead>
  318.        <row>
  319. <entry>Function</entry>
  320. <entry>Returns</entry>
  321. <entry>Description</entry>
  322. <entry>Example</entry>
  323.        </row>
  324.       </thead>
  325.       <tbody>
  326.        <row>
  327. <entry> abstime(datetime) </entry>
  328. <entry> abstime </entry>
  329. <entry> convert to abstime </entry>
  330. <entry> abstime('now'::datetime) </entry>
  331.        </row>
  332.        <row>
  333. <entry> age(datetime,datetime) </entry>
  334. <entry> timespan </entry>
  335. <entry> preserve months and years </entry>
  336. <entry> age('now','1957-06-13'::datetime) </entry>
  337.        </row>
  338.        <row>
  339. <entry> datetime(abstime) </entry>
  340. <entry> datetime </entry>
  341. <entry> convert to datetime </entry>
  342. <entry> datetime('now'::abstime) </entry>
  343.        </row>
  344.        <row>
  345. <entry> datetime(date) </entry>
  346. <entry> datetime </entry>
  347. <entry> convert to datetime </entry>
  348. <entry> datetime('today'::date) </entry>
  349.        </row>
  350.        <row>
  351. <entry> datetime(date,time) </entry>
  352. <entry> datetime </entry>
  353. <entry> convert to datetime </entry>
  354. <entry> datetime('1998-02-24'::datetime, '23:07'::time); </entry>
  355.   </row>
  356.        <row>
  357. <entry> date_part(text,datetime) </entry>
  358. <entry> float8 </entry>
  359. <entry> portion of date </entry>
  360. <entry> date_part('dow','now'::datetime) </entry>
  361.        </row>
  362.        <row>
  363. <entry> date_part(text,timespan) </entry>
  364. <entry> float8 </entry>
  365. <entry> portion of time </entry>
  366. <entry> date_part('hour','4 hrs 3 mins'::timespan) </entry>
  367.        </row>
  368.        <row>
  369. <entry> date_trunc(text,datetime) </entry>
  370. <entry> datetime </entry>
  371. <entry> truncate date </entry>
  372. <entry> date_trunc('month','now'::abstime) </entry>
  373.        </row>
  374.        <row>
  375. <entry> isfinite(abstime) </entry>
  376. <entry> bool </entry>
  377. <entry> a finite time? </entry>
  378. <entry> isfinite('now'::abstime) </entry>
  379.        </row>
  380.        <row>
  381. <entry> isfinite(datetime) </entry>
  382. <entry> bool </entry>
  383. <entry> a finite time? </entry>
  384. <entry> isfinite('now'::datetime) </entry>
  385.        </row>
  386.        <row>
  387. <entry> isfinite(timespan) </entry>
  388. <entry> bool </entry>
  389. <entry> a finite time? </entry>
  390. <entry> isfinite('4 hrs'::timespan) </entry>
  391.        </row>
  392.        <row>
  393. <entry> reltime(timespan) </entry>
  394. <entry> reltime </entry>
  395. <entry> convert to reltime </entry>
  396. <entry> reltime('4 hrs'::timespan) </entry>
  397.        </row>
  398.        <row>
  399. <entry> timespan(reltime) </entry>
  400. <entry> timespan </entry>
  401. <entry> convert to timespan </entry>
  402. <entry> timespan('4 hours'::reltime) </entry>
  403.        </row>
  404.       </tbody>
  405.      </tgroup>
  406.     </table>
  407.    </para>
  409.    <para>
  410.     For the
  411.     <function>date_part</function> and <function>date_trunc</function>
  412.     functions, arguments can be
  413.     `year', `month', `day', `hour', `minute', and `second',
  414.     as well as the more specialized quantities
  415.     `decade', `century', `millenium', `millisecond', and `microsecond'.
  416.     <function>date_part</function> allows `dow'
  417.     to return day of week and `epoch' to return seconds since 1970
  418.     (for <type>datetime</type>)
  419.     or 'epoch' to return total elapsed seconds (for <type>timespan</type>).
  420.    </para>
  421.   </sect1>
  423.   <sect1>
  424.    <title>Geometric Functions</title>
  426.    <para>
  427.     The geometric types point, box, lseg, line, path, polygon, and
  428.     circle have a large set of native support functions.
  429.    </para>
  431.    <para>
  432.     <table tocentry="1">
  433.      <title>Geometric Functions</title>
  434.      <tgroup cols="4">
  435.       <thead>
  436.        <row>
  437. <entry>Function</entry>
  438. <entry>Returns</entry>
  439. <entry>Description</entry>
  440. <entry>Example</entry>
  441.        </row>
  442.       </thead>
  443.       <tbody>
  444.        <row>
  445. <entry> area(box) </entry>
  446. <entry> float8 </entry>
  447. <entry> area of box </entry>
  448. <entry> area('((0,0),(1,1))'::box) </entry>
  449.        </row>
  450.        <row>
  451. <entry> area(circle) </entry>
  452. <entry> float8 </entry>
  453. <entry> area of circle </entry>
  454. <entry> area('((0,0),2.0)'::circle) </entry>
  455.        </row>
  456.        <row>
  457. <entry> box(box,box) </entry>
  458. <entry> box </entry>
  459. <entry> boxes to intersection box </entry>
  460. <entry> box('((0,0),(1,1))','((0.5,0.5),(2,2))') </entry>
  461.        </row>
  462.        <row>
  463. <entry> center(box) </entry>
  464. <entry> point </entry>
  465. <entry> center of object </entry>
  466. <entry> center('((0,0),(1,2))'::box) </entry>
  467.        </row>
  468.        <row>
  469. <entry> center(circle) </entry>
  470. <entry> point </entry>
  471. <entry> center of object </entry>
  472. <entry> center('((0,0),2.0)'::circle) </entry>
  473.        </row>
  474.        <row>
  475. <entry> diameter(circle) </entry>
  476. <entry> float8 </entry>
  477. <entry> diameter of circle </entry>
  478. <entry> diameter('((0,0),2.0)'::circle) </entry>
  479.        </row>
  480.        <row>
  481. <entry> height(box) </entry>
  482. <entry> float8 </entry>
  483. <entry> vertical size of box </entry>
  484. <entry> height('((0,0),(1,1))'::box) </entry>
  485.        </row>
  486.        <row>
  487. <entry> isclosed(path) </entry>
  488. <entry> bool </entry>
  489. <entry> a closed path? </entry>
  490. <entry> isclosed('((0,0),(1,1),(2,0))'::path) </entry>
  491.        </row>
  492.        <row>
  493. <entry> isopen(path) </entry>
  494. <entry> bool </entry>
  495. <entry> an open path? </entry>
  496. <entry> isopen('[(0,0),(1,1),(2,0)]'::path) </entry>
  497.        </row>
  498.        <row>
  499. <entry> length(lseg) </entry>
  500. <entry> float8 </entry>
  501. <entry> length of line segment </entry>
  502. <entry> length('((-1,0),(1,0))'::lseg) </entry>
  503.        </row>
  504.        <row>
  505. <entry> length(path) </entry>
  506. <entry> float8 </entry>
  507. <entry> length of path </entry>
  508. <entry> length('((0,0),(1,1),(2,0))'::path) </entry>
  509.        </row>
  510.        <row>
  511. <entry> pclose(path) </entry>
  512. <entry> path </entry>
  513. <entry> convert path to closed </entry>
  514. <entry> popen('[(0,0),(1,1),(2,0)]'::path) </entry>
  515.        </row>
  516.        <row>
  517. <entry> point(lseg,lseg) </entry>
  518. <entry> point </entry>
  519. <entry> intersection </entry>
  520. <entry> point('((-1,0),(1,0))'::lseg,'((-2,-2),(2,2))'::lseg) </entry>
  521.        </row>
  522.        <row>
  523. <entry> points(path) </entry>
  524. <entry> int4 </entry>
  525. <entry> number of points </entry>
  526. <entry> points('[(0,0),(1,1),(2,0)]'::path) </entry>
  527.        </row>
  528.        <row>
  529. <entry> popen(path) </entry>
  530. <entry> path </entry>
  531. <entry> convert path to open </entry>
  532. <entry> popen('((0,0),(1,1),(2,0))'::path) </entry>
  533.        </row>
  534.        <row>
  535. <entry> radius(circle) </entry>
  536. <entry> float8 </entry>
  537. <entry> radius of circle </entry>
  538. <entry> radius('((0,0),2.0)'::circle) </entry>
  539.        </row>
  540.        <row>
  541. <entry> width(box) </entry>
  542. <entry> float8 </entry>
  543. <entry> horizontal size </entry>
  544. <entry> width('((0,0),(1,1))'::box) </entry>
  545.        </row>
  546.       </tbody>
  547.      </tgroup>
  548.     </table>
  549.    </para>
  551.    <para>
  552.     <table tocentry="1">
  553.      <title>Geometric Type Conversion Functions</title>
  554.      <tgroup cols="4">
  555.       <thead>
  556.        <row>
  557. <entry>Function</entry>
  558. <entry>Returns</entry>
  559. <entry>Description</entry>
  560. <entry>Example</entry>
  561.        </row>
  562.       </thead>
  563.       <tbody>
  564.        <row>
  565. <entry> box(circle) </entry>
  566. <entry> box </entry>
  567. <entry> convert circle to box </entry>
  568. <entry> box('((0,0),2.0)'::circle) </entry>
  569.        </row>
  570.        <row>
  571. <entry> box(point,point) </entry>
  572. <entry> box </entry>
  573. <entry> convert points to box </entry>
  574. <entry> box('(0,0)'::point,'(1,1)'::point) </entry>
  575.        </row>
  576.        <row>
  577. <entry> box(polygon) </entry>
  578. <entry> box </entry>
  579. <entry> convert polygon to box </entry>
  580. <entry> box('((0,0),(1,1),(2,0))'::polygon) </entry>
  581.        </row>
  582.        <row>
  583. <entry> circle(box) </entry>
  584. <entry> circle </entry>
  585. <entry> convert to circle </entry>
  586. <entry> circle('((0,0),(1,1))'::box) </entry>
  587.        </row>
  588.        <row>
  589. <entry> circle(point,float8) </entry>
  590. <entry> circle </entry>
  591. <entry> convert to circle </entry>
  592. <entry> circle('(0,0)'::point,2.0) </entry>
  593.        </row>
  594.        <row>
  595. <entry> lseg(box) </entry>
  596. <entry> lseg </entry>
  597. <entry> convert diagonal to lseg </entry>
  598. <entry> lseg('((-1,0),(1,0))'::box) </entry>
  599.        </row>
  600.        <row>
  601. <entry> lseg(point,point) </entry>
  602. <entry> lseg </entry>
  603. <entry> convert to lseg </entry>
  604. <entry> lseg('(-1,0)'::point,'(1,0)'::point) </entry>
  605.        </row>
  606.        <row>
  607. <entry> path(polygon) </entry>
  608. <entry> point </entry>
  609. <entry> convert to path </entry>
  610. <entry> path('((0,0),(1,1),(2,0))'::polygon) </entry>
  611.        </row>
  612.        <row>
  613. <entry> point(circle) </entry>
  614. <entry> point </entry>
  615. <entry> convert to point (center) </entry>
  616. <entry> point('((0,0),2.0)'::circle) </entry>
  617.        </row>
  618.        <row>
  619. <entry> point(lseg,lseg) </entry>
  620. <entry> point </entry>
  621. <entry> convert to point (intersection) </entry>
  622. <entry> point('((-1,0),(1,0))'::lseg, '((-2,-2),(2,2))'::lseg) </entry>
  623.        </row>
  624.        <row>
  625. <entry> point(polygon) </entry>
  626. <entry> point </entry>
  627. <entry> center of polygon </entry>
  628. <entry> point('((0,0),(1,1),(2,0))'::polygon) </entry>
  629.        </row>
  630.        <row>
  631. <entry> polygon(box) </entry>
  632. <entry> polygon </entry>
  633. <entry> convert to polygon with 12 points </entry>
  634. <entry> polygon('((0,0),(1,1))'::box) </entry>
  635.        </row>
  636.        <row>
  637. <entry> polygon(circle) </entry>
  638. <entry> polygon </entry>
  639. <entry> convert to 12-point polygon </entry>
  640. <entry> polygon('((0,0),2.0)'::circle) </entry>
  641.        </row>
  642.        <row>
  643. <entry> polygon(<replaceable class="parameter">npts</replaceable>,circle) </entry>
  644. <entry> polygon </entry>
  645. <entry> convert to <replaceable class="parameter">npts</replaceable> polygon </entry>
  646. <entry> polygon(12,'((0,0),2.0)'::circle) </entry>
  647.        </row>
  648.        <row>
  649. <entry> polygon(path) </entry>
  650. <entry> polygon </entry>
  651. <entry> convert to polygon </entry>
  652. <entry> polygon('((0,0),(1,1),(2,0))'::path) </entry>
  653.        </row>
  654.       </tbody>
  655.      </tgroup>
  656.     </table>
  657.    </para>
  659.    <para>
  660.     <table tocentry="1">
  661.      <title>Geometric Upgrade Functions</title>
  662.      <tgroup cols="4">
  663.       <thead>
  664.        <row>
  665. <entry>Function</entry>
  666. <entry>Returns</entry>
  667. <entry>Description</entry>
  668. <entry>Example</entry>
  669.        </row>
  670.       </thead>
  671.       <tbody>
  672.        <row>
  673. <entry> isoldpath(path) </entry>
  674. <entry> path </entry>
  675. <entry> test path for pre-v6.1 form </entry>
  676. <entry> isoldpath('(1,3,0,0,1,1,2,0)'::path) </entry>
  677.        </row>
  678.        <row>
  679. <entry> revertpoly(polygon) </entry>
  680. <entry> polygon </entry>
  681. <entry> convert pre-v6.1 polygon </entry>
  682. <entry> revertpoly('((0,0),(1,1),(2,0))'::polygon) </entry>
  683.        </row>
  684.        <row>
  685. <entry> upgradepath(path) </entry>
  686. <entry> path </entry>
  687. <entry> convert pre-v6.1 path </entry>
  688. <entry> upgradepath('(1,3,0,0,1,1,2,0)'::path) </entry>
  689.        </row>
  690.        <row>
  691. <entry> upgradepoly(polygon) </entry>
  692. <entry> polygon </entry>
  693. <entry> convert pre-v6.1 polygon </entry>
  694. <entry> upgradepoly('(0,1,2,0,1,0)'::polygon) </entry>
  695.        </row>
  696.       </tbody>
  697.      </tgroup>
  698.     </table>
  699.    </para>
  700.   </sect1>
  702.   <sect1>
  703.    <title id="cidr-funcs">IP V4 Functions</title>
  705.    <para>
  706.     <table tocentry="1">
  707.      <title><productname>Postgres</productname>IP V4 Functions</title>
  708.      <tgroup cols="4">
  709.       <thead>
  710.        <row>
  711. <entry>Function</entry>
  712. <entry>Returns</entry>
  713. <entry>Description</entry>
  714. <entry>Example</entry>
  715.        </row>
  716.       </thead>
  717.       <tbody>
  718.        <row>
  719. <entry> broadcast(cidr) </entry>
  720. <entry> text </entry>
  721. <entry> construct broadcast address as text </entry>
  722. <entry> broadcast('192.168.1.5/24') </entry>
  723.        </row>
  724.        <row>
  725. <entry> broadcast(inet) </entry>
  726. <entry> text </entry>
  727. <entry> construct broadcast address as text </entry>
  728. <entry> broadcast('192.168.1.5/24') </entry>
  729.        </row>
  730.        <row>
  731. <entry> host(inet) </entry>
  732. <entry> text </entry>
  733. <entry> extract host address as text </entry>
  734. <entry> host('192.168.1.5/24') </entry>
  735.        </row>
  736.        <row>
  737. <entry> masklen(cidr) </entry>
  738. <entry> int4 </entry>
  739. <entry> calculate netmask length </entry>
  740. <entry> masklen('192.168.1.5/24') </entry>
  741.        </row>
  742.        <row>
  743. <entry> masklen(inet) </entry>
  744. <entry> int4 </entry>
  745. <entry> calculate netmask length </entry>
  746. <entry> masklen('192.168.1.5/24') </entry>
  747.        </row>
  748.        <row>
  749. <entry> netmask(inet) </entry>
  750. <entry> text </entry>
  751. <entry> construct netmask as text </entry>
  752. <entry> netmask('192.168.1.5/24') </entry>
  753.        </row>
  754.       </tbody>
  755.      </tgroup>
  756.     </table>
  757.    </para>
  759.   </sect1>
  761.  </chapter>
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