select * from t_hq_ryxx;select bianh,xingm from t_hq_ryxx;--為字段名定義別名 select bianh as 編號,xingm as 姓名 from t_hq_ryxx;select bianh 編號 from t_hq_ryxx;select bianh || xingm as 編號和姓名 from t_hq_ryxx;select bianh as bh, t.* from t_hq_ryxx t order by bianh desc;--order by 排序,desc降序排序 select bianh as bh, t.* from t_hq_ryxx t order by xingb desc,bum desc;--nulls last/first的用法,desc或者asc要放在nulls前面 select bianh ,xingm ,bum,xingb from t_hq_ryxx t order by bum desc nulls last,xingb;--選擇排序為8的字段 select * from t_hq_ryxx order by 8;--由bum和bianh列來定義排序方式 select * from t_hq_ryxx order by bum || bianh; --相加的字段若有空則結果為空 select * from t_hq_ryxx order by nianl + gongz;select nianl,gongz, (nianl + gongz) as g from t_hq_ryxx order by (nianl + gongz) desc; --為字段的和定義別名,并以此為排序定義方式 select nianl,gongz, (nianl + gongz) as g from t_hq_ryxx order by g;select * from t_hq_ryxx; --選擇bum為102或者103,性別為女的行 select * from t_hq_ryxx where (bum = '102' or bum = '103') and xingb = 2; --選擇bum不為空的行 select * from t_hq_ryxx where bum is not null;--去重復 select distinct bum,xingb from t_hq_ryxx;--模糊查詢 % 通配符 _ 通配一位 select * from t_hq_ryxx where xingm like '%阿%';select * from t_hq_ryxx where bianh in ('101','103','105');select * from t_hq_ryxx where bianh = '101' or bianh = '103' or bianh = '105';select * from t_hq_ryxx where gongz between '1000' and '2000';select * from t_hq_ryxx where gongz >= 1000 and gongz <= 2000;--子查詢 select * from t_hq_ryxx where bum in (select bumenbm from t_hq_bm where lianxidh = '911');select * from t_hq_ryxx where gongz > all (select pingjgz from t_hq_bm);--分組- select bum, count(1) as 數量 from t_hq_ryxx group by bum;select bum, count(1) as 數量,avg(gongz) as 平均值,sum(gongz) as 合計 from t_hq_ryxx group by bianh, bum; --分組基礎上過濾 select bum, count(1) as 數量,avg(gongz) as 平均值,sum(gongz) as 合計 from t_hq_ryxx group by bum having avg(gongz) > 2000;select bum, count(1) as 數量,avg(gongz) as 平均值,sum(gongz) as 合計 from t_hq_ryxx where bum is not null group by bum having avg(gongz) > 2000;

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轉載于:https://www.cnblogs.com/shadowduke/p/4915695.html

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