DQL查询语言-概述

DQL：Data Query Language

SELECT
-- ↓查询源参数
[ALL | DISTINCT | DISTINCTROW ]
[HIGH_PRIORITY]
[STRAIGHT_JOIN]
[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
[SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
--  ↓查询的列名
select_expr, ...
-- ↓文件输出配置
[
    INTO OUTFILE 'file_name' export_options |
    INTO DUMPFILE 'file_name'
]
-- ↓查询表源配置
[
    -- ↓表名
    FROM table_references
    -- ↓条件
    [WHERE where_definition]
    -- ↓分组
    [
        GROUP BY {col_name | expr | position}
        [ASC | DESC], ... [WITH ROLLUP]
    ]
    -- ↓
    [HAVING where_definition]
    -- ↓排序
    [
        ORDER BY {col_name | expr | position}
        [ASC | DESC] ,
        ...
    ]
    -- ↓结果分页
    [
        LIMIT {[offset,] row_count | row_count OFFSET offset}
    ]
    [PROCEDURE procedure_name(argument_list)]
    [FOR UPDATE | LOCK IN SHARE MODE]
]

当字段和关键字一样的时候，建议使用单斜点包裹。