oralce 笔记
查某一表的行數?
select max(rownum) from tablename插入數據之前判斷是否重復
insert into tablename (coloum1,coloum2) select coloum1,coloum2 from dual where not exists( select 1 from tablename where coloum1 ="value1" and coloum2="value2";查詢時檢索數據庫中字段?
select coloum1 , coloum1 ,coloum3 from table where instr('coloum1',查詢字符)>0 or instr('coloum3',查詢字符)>0 or instr('coloum3',查詢字符)>0去除表中有字段為空的數據
delete from table where coloum is null ;
轉載于:https://www.cnblogs.com/vitre/p/5101991.html
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