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Overview
| Comment: | Fix typos in the windowfunctions.html document. |
|---|---|
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
221cce4209f950a4b91372aed71f477d |
| User & Date: | drh 2018-09-12 10:49:36 |
Context
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2018-09-13
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| 12:50 | Updates to the geopoly documentation. check-in: f1742a52f5 user: drh tags: trunk | |
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2018-09-12
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| 10:49 | Fix typos in the windowfunctions.html document. check-in: 221cce4209 user: drh tags: trunk | |
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2018-09-11
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| 22:44 | Fix typos in the geopoly document. check-in: 81cf14c724 user: drh tags: trunk | |
Changes
Changes to pages/windowfunctions.in.
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presence of an OVER clause. If a function invocation has an OVER clause then it is a window function, and if lacks a OVER clause it is an ordinary function. Window functions might also have a FILTER clause in between the function and the OVER clause. <p>Unlike ordinary functions, window functions cannot use the DISTINCT keyword. Also, Window functions may only appears in the result set and in the ORDER BY clause of a SELECT statement. <p>The following simple table is used to demonstrate how window functions work: <codeblock> CREATE TABLE t0(x INTEGER PRIMARY KEY, y TEXT); ................................................................................ non-negative integer. In this case the value returned is the result of evaluating <i>expr</i> against the row <i>offset</i> rows before the current row within the partition. If <i>offset</i> is 0, then <i>expr</i> is evaluated against the current row. If there is no row <i>offset</i> rows before the current row, NULL is returned. <p> If <i>default</i> is also provided, then it is returned instead of NULL if row identified by <i>offset</i> does not exist. <dt><p><b>lead(expr)<br>lead(expr, offset)<br>lead(expr, offset, default)</b> <dd><p> The first form of the lead() function returns the result of evaluating expression <i>expr</i> against the next row in the partition. Or, if there is no next row (because the current row is the last), NULL. <p> If the <i>offset</i> argument is provided, then it must be a ................................................................................ non-negative integer. In this case the value returned is the result of evaluating <i>expr</i> against the row <i>offset</i> rows after the current row within the partition. If <i>offset</i> is 0, then <i>expr</i> is evaluated against the current row. If there is no row <i>offset</i> rows after the current row, NULL is returned. <p> If <i>default</i> is also provided, then it is returned instead of NULL if row identified by <i>offset</i> does not exist. <dt><p><b>first_value(expr)</b> <dd><p> This built-in window function calculates the window frame for each row in the same way as an aggregate window function. It returns the value of <i>expr</i> evaluated against the first row in the window frame for each row. <dt><p><b>last_value(expr)</b> <dd><p> This built-in window function calculates the window frame for each |
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presence of an OVER clause. If a function invocation has an OVER clause then it is a window function, and if lacks a OVER clause it is an ordinary function. Window functions might also have a FILTER clause in between the function and the OVER clause. <p>Unlike ordinary functions, window functions cannot use the DISTINCT keyword. Also, Window functions may only appear in the result set and in the ORDER BY clause of a SELECT statement. <p>The following simple table is used to demonstrate how window functions work: <codeblock> CREATE TABLE t0(x INTEGER PRIMARY KEY, y TEXT); ................................................................................ non-negative integer. In this case the value returned is the result of evaluating <i>expr</i> against the row <i>offset</i> rows before the current row within the partition. If <i>offset</i> is 0, then <i>expr</i> is evaluated against the current row. If there is no row <i>offset</i> rows before the current row, NULL is returned. <p> If <i>default</i> is also provided, then it is returned instead of NULL if the row identified by <i>offset</i> does not exist. <dt><p><b>lead(expr)<br>lead(expr, offset)<br>lead(expr, offset, default)</b> <dd><p> The first form of the lead() function returns the result of evaluating expression <i>expr</i> against the next row in the partition. Or, if there is no next row (because the current row is the last), NULL. <p> If the <i>offset</i> argument is provided, then it must be a ................................................................................ non-negative integer. In this case the value returned is the result of evaluating <i>expr</i> against the row <i>offset</i> rows after the current row within the partition. If <i>offset</i> is 0, then <i>expr</i> is evaluated against the current row. If there is no row <i>offset</i> rows after the current row, NULL is returned. <p> If <i>default</i> is also provided, then it is returned instead of NULL if the row identified by <i>offset</i> does not exist. <dt><p><b>first_value(expr)</b> <dd><p> This built-in window function calculates the window frame for each row in the same way as an aggregate window function. It returns the value of <i>expr</i> evaluated against the first row in the window frame for each row. <dt><p><b>last_value(expr)</b> <dd><p> This built-in window function calculates the window frame for each |