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Su, Xiaomeng
76a5b1ee83
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com> Co-authored-by: Su, Xiaomeng <suxiaomeng1@huawei.com> Co-committed-by: Su, Xiaomeng <suxiaomeng1@huawei.com>
69 lines
9.4 KiB
HTML
69 lines
9.4 KiB
HTML
<a name="dli_spark_ltrim"></a><a name="dli_spark_ltrim"></a>
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<h1 class="topictitle1">ltrim</h1>
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<div id="body8662426"><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p16304151132511">This function is used to remove characters from the left of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b396514502348">str</strong>.</p>
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<ul id="dli_spark_ltrim__en-us_topic_0000001696338813_ul12997182472913"><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li15997824122913">If <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b21461053358">trimChars</strong> is not specified, spaces are removed by default.</li><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li49972243297">If <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b1847867183414">trimChars</strong> is specified, the function removes the longest possible substring from the left end of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b2043572803416">str</strong> that consists of characters in the <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b85133428348">trimChars</strong> set.</li></ul>
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<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p167161339419">Similar functions:</p>
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<ul id="dli_spark_ltrim__en-us_topic_0000001696338813_ul151387820415"><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li1313808114111"><a href="dli_spark_rtrim.html#dli_spark_rtrim">rtrim</a>. This function is used to remove characters from the right of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b1511814454377">str</strong>.</li><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li128681630134117"><a href="dli_spark_trim.html#dli_spark_trim">trim</a>. This function is used to remove characters from the left and right of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b215703143814">str</strong>.</li></ul>
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<div class="section" id="dli_spark_ltrim__en-us_topic_0000001696338813_section45291954203217"><h4 class="sectiontitle">Syntax</h4><pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen10637184423619">ltrim([<trimChars>,] string <str>)</pre>
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</div>
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<div class="section" id="dli_spark_ltrim__en-us_topic_0000001696338813_section992014913317"><h4 class="sectiontitle">Parameters</h4>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="dli_spark_ltrim__en-us_topic_0000001696338813_table1829154762513" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Parameters</caption><thead align="left"><tr id="dli_spark_ltrim__en-us_topic_0000001696338813_row8830104792517"><th align="left" class="cellrowborder" valign="top" width="19.220000000000002%" id="mcps1.3.6.2.2.5.1.1"><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p983074711252">Parameter</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="13.420000000000002%" id="mcps1.3.6.2.2.5.1.2"><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p6830124732517">Mandatory</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="15.590000000000002%" id="mcps1.3.6.2.2.5.1.3"><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p13318164512614">Type</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="51.77%" id="mcps1.3.6.2.2.5.1.4"><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p08301547132513">Description</p>
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</th>
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</tr>
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</thead>
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<tbody><tr id="dli_spark_ltrim__en-us_topic_0000001696338813_row199266231004"><td class="cellrowborder" valign="top" width="19.220000000000002%" headers="mcps1.3.6.2.2.5.1.1 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p1084712712254">str</p>
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</td>
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<td class="cellrowborder" valign="top" width="13.420000000000002%" headers="mcps1.3.6.2.2.5.1.2 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p1937912389241">Yes</p>
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</td>
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<td class="cellrowborder" valign="top" width="15.590000000000002%" headers="mcps1.3.6.2.2.5.1.3 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p183791038192411">STRING</p>
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</td>
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<td class="cellrowborder" valign="top" width="51.77%" headers="mcps1.3.6.2.2.5.1.4 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p99134255019">String from which characters on the left are to be removed. If the value is of the BIGINT, DECIMAL, DOUBLE, or DATETIME type, the value is implicitly converted to the STRING type for calculation.</p>
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</td>
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</tr>
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<tr id="dli_spark_ltrim__en-us_topic_0000001696338813_row138061989595"><td class="cellrowborder" valign="top" width="19.220000000000002%" headers="mcps1.3.6.2.2.5.1.1 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p1445253210254">trimChars</p>
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</td>
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<td class="cellrowborder" valign="top" width="13.420000000000002%" headers="mcps1.3.6.2.2.5.1.2 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p1228018496242">Yes</p>
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</td>
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<td class="cellrowborder" valign="top" width="15.590000000000002%" headers="mcps1.3.6.2.2.5.1.3 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p3260123221212">STRING</p>
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</td>
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<td class="cellrowborder" valign="top" width="51.77%" headers="mcps1.3.6.2.2.5.1.4 "><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p784415518499">Characters to be removed</p>
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</td>
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</tr>
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</tbody>
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</table>
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</div>
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</div>
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<div class="section" id="dli_spark_ltrim__en-us_topic_0000001696338813_section210162513312"><h4 class="sectiontitle">Return Values</h4><p id="dli_spark_ltrim__en-us_topic_0000001696338813_p12141539203010">The return value is of the STRING type.</p>
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<div class="note" id="dli_spark_ltrim__en-us_topic_0000001696338813_note61422099395"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="dli_spark_ltrim__en-us_topic_0000001696338813_ul1378265112713"><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li1878235117270">If the value of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b80822001643450">str</strong> is not of the STRING, BIGINT, DOUBLE, DECIMAL, or DATETIME type, an error is reported.</li><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li64979474309">If the value of <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b250919484391">str</strong> or <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b1051074813392">trimChars</strong> is <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b1851064812394">NULL</strong>, <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b951074883911">NULL</strong> is returned.</li></ul>
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</div></div>
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</div>
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<div class="section" id="dli_spark_ltrim__en-us_topic_0000001696338813_section13277192233920"><h4 class="sectiontitle">Example Code</h4><ul id="dli_spark_ltrim__en-us_topic_0000001696338813_ul1938816173116"><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li1193801683113">Removes spaces on the left of string <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b999214242403">abc</strong>. An example command is as follows:<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p5251522171316">The value <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b177981537164019">stringabc</strong> is returned.</p>
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<pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen54225272131">select ltrim(' abc');</pre>
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<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p125117226136">It is equivalent to the following statement:</p>
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<pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen171276315136">select trim(leading from ' abc');</pre>
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<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p10355131411232"><strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b153521425414">leading</strong> indicates that the leading spaces in a string are removed.</p>
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</li><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li1493813168310">The value of the input parameter is <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b143635896743625">NULL</strong>. An example command is as follows:<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p10857204081317">The value <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b147614614418">NULL</strong> is returned.</p>
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<pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen2159749101312">select ltrim(null);
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select ltrim('xy', null);
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select ltrim(null, 'xy');</pre>
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</li><li id="dli_spark_ltrim__en-us_topic_0000001696338813_li1893821610313">Removes all substrings from the left end of the string <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b2010953293510">yxlucyxx</strong> that consist of characters in the set <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b191827446358">xy</strong>.<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p891411516268">The function returns <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b1958172710387">lucyxx</strong>, as any substring starting with <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b12133113517384">x</strong> or <strong id="dli_spark_ltrim__en-us_topic_0000001696338813_b18936193910381">y</strong> from the left end is removed.</p>
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<pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen10306111732612">select ltrim( 'xy','yxlucyxx'); </pre>
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<p id="dli_spark_ltrim__en-us_topic_0000001696338813_p19144512614">It is equivalent to the following statement:</p>
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<pre class="screen" id="dli_spark_ltrim__en-us_topic_0000001696338813_screen17481182232613">select trim(leading 'xy' from 'yxlucyxx');</pre>
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</li></ul>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="dli_08_0472.html">String Functions</a></div>
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</div>
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</div>
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