ANSI支持的Select Count SQLStatements [英] ANSI Support of Select Count SQLStatements

问题描述

我想知道每个ANSI标准是否都有受支持的Select Count SQL语句列表?以下是我所知道的三种变化.可以在以下所有三个选项上使用where子句吗?

I'm wondering if there is a list of supported Select Count SQL statements per the ANSI standard? The below three variations are what I know of. Can the where clause be used on all three below?

SELECT COUNT(*) AS RowCount FROM table_name
SELECT COUNT(ColumnName) AS RowCount FROM table_name
SELECT COUNT(DISTINCT ColumnName) AS RowCount FROM table_name

推荐答案

几乎所有DBMS都使用的SQL标准是ANSI 92标准，可以在

The SQL standard that almost all DBMS's use is the ANSI 92 standard, which can be found at http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt. Page 124 has the information that you are looking for. Most DBMSs offer something in addition to the ANSI 92 standard, but this is kind of the lowest common denominator of all of them.

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