lang_expr.html

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          </tr>
          <tr>
            <td align="right" width="1%" nowrap>
              <i><font color="#ff3434">like-op</font></i> ::=</td>
            <td>
              <b><font color="#2c2cf0">LIKE </font></b><big>|</big><b><font color="#2c2cf0"> GLOB
              </font></b><big>|</big><b><font color="#2c2cf0"> REGEXP </font></b><big>|</big><b><font
                color="#2c2cf0"> MATCH</font></b></td>
          </tr>
        </table>
      </p>
      <p>
        This section is different from the others. Most other sections of this document
        talks about a particular SQL command. This section does not talk about a standalone
        command but about "expressions" which are subcomponents of most other commands.</p>
      <p>
        SQLite understands the following binary operators, in order from highest to lowest
        precedence:</p>
      <blockquote>
        <pre><font color="#2c2cf0"><big>|| * / % + - &lt;&lt; &gt;&gt; &amp; | &lt; &lt;= &gt;
  &gt;= = == != &lt;&gt; </big>IN AND OR</font>
</pre>
      </blockquote>
      <p>
        Supported unary operators are these:</p>
      <blockquote>
        <pre><font color="#2c2cf0"><big>- + ! ~ NOT</big></font>
</pre>
      </blockquote>
      <p>
        The unary operator [Operator +] is a no-op. It can be applied to strings, numbers,
        or blobs and it always gives as its result the value of the operand.</p>
      <p>
        Note that there are two variations of the equals and not equals operators. Equals
        can be either <font color="#2c2cf0"><big>=</big></font> or <font color="#2c2cf0"><big>
          ==</big></font>. The non-equals operator can be either <font color="#2c2cf0"><big>
            !=</big></font> or <font color="#2c2cf0"><big>&lt;&gt;</big></font>. The <font color="#2c2cf0">
              <big>||</big></font> operator is "concatenate" - it joins together the two
        strings of its operands. The operator <font color="#2c2cf0"><big>%</big></font>
        outputs the remainder of its left operand modulo its right operand.</p>
      <p>
        The result of any binary operator is a numeric value, except for the <font color="#2c2cf0">
          <big>||</big></font> concatenation operator which gives a string result.</p>
      <a name="literal_value"></a>
      <p>
        A literal value is an integer number or a floating point number. Scientific notation
        is supported. The "." character is always used as the decimal point even if the
        locale setting specifies "," for this role - the use of "," for the decimal point
        would result in syntactic ambiguity. A string constant is formed by enclosing the
        string in single quotes ('). A single quote within the string can be encoded by
        putting two single quotes in a row - as in Pascal. C-style escapes using the backslash
        character are not supported because they are not standard SQL. BLOB literals are
        string literals containing hexadecimal data and preceded by a single "x" or "X"
        character. For example:</p>
      <blockquote>
        <pre>X'53514697465'
</pre>
      </blockquote>
      <p>
        A literal value can also be the token "NULL".
      </p>
      <p>
        A parameter specifies a placeholder in the expression for a literal value that is
        filled in at runtime using the <a href="capi3ref.html#sqlite3_bind_int">sqlite3_bind</a>
        API. Parameters can take several forms:
      </p>
      <p>
        <table>
          <tr>
            <td align="right" width="1%" nowrap>
              <b>?</b><i>NNN</i></td>
            <td width="20">
            </td>
            <td>
              A question mark followed by a number <i>NNN</i> holds a spot for the NNN-th parameter.
              NNN must be between 1 and 999.</td>
          </tr>
          <tr>
            <td align="right" width="1%" nowrap>
              <b>?</b></td>
            <td width="20">
            </td>
            <td>
              A question mark that is not followed by a number holds a spot for the next unused
              parameter.</td>
          </tr>
          <tr>
            <td align="right" width="1%" nowrap>
              <b>:</b><i>AAAA</i></td>
            <td width="20">
            </td>
            <td>
              A colon followed by an identifier name holds a spot for a named parameter with the
              name AAAA. Named parameters are also numbered. The number assigned is the next unused
              number. To avoid confusion, it is best to avoid mixing named and numbered parameters.</td>
          </tr>
          <tr>
            <td align="right" width="1%" nowrap>
              <b>@</b><i>AAAA</i></td>
            <td width="20">
            </td>
            <td>
              An "at" sign works exactly like a colon.</td>
          </tr>
          <tr>
            <td align="right" width="1%" nowrap>
              <b>$</b><i>AAAA</i></td>
            <td width="20">
            </td>
            <td>
              A dollar-sign followed by an identifier name also holds a spot for a named parameter
              with the name AAAA. The identifier name in this case can include one or more occurances
              of "::" and a suffix enclosed in "(...)" containing any text at all. This syntax
              is the form of a variable name in the Tcl programming language.</td>
          </tr>
        </table>
      </p>
      <blockquote>
      </blockquote>
      <p>
        Parameters that are not assigned values using <a href="capi3ref.html#sqlite3_bind_int">
          sqlite3_bind</a> are treated as NULL.</p>
      <a name="like"></a>
      <p>
        The LIKE operator does a pattern matching comparison. The operand to the right contains
        the pattern, the left hand operand contains the string to match against the pattern.
        A percent symbol <font color="#2c2cf0"><big>%</big></font> in the pattern matches
        any sequence of zero or more characters in the string. An underscore <font color="#2c2cf0">
          <big>_</big></font> in the pattern matches any single character in the string.
        Any other character matches itself or it's lower/upper case equivalent (i.e. case-insensitive
        matching). (A bug: SQLite only understands upper/lower case for 7-bit Latin characters.
        Hence the LIKE operator is case sensitive for 8-bit iso8859 characters or UTF-8
        characters. For example, the expression <b>'a' LIKE 'A'</b> is TRUE but <b>'