mysql數(shù)據(jù)記錄查詢

1、p簡單數(shù)據(jù)記錄查詢p條件數(shù)據(jù)記錄查詢p排序數(shù)據(jù)記錄查詢p限制數(shù)據(jù)記錄查詢數(shù)量p統(tǒng)計函數(shù)和分組數(shù)據(jù)記錄查詢查詢所有字段數(shù)據(jù)Select * from table_name等效查詢Select allfield from table_name查詢指定字段數(shù)據(jù)SELECT field1 field2 fieldn FROM table_nameSELECT field2 field1 fieldn FROM table_name避免重復數(shù)據(jù)查詢DISTINCTSELECT field1 field2 fieldn FROM table_nameSELECT field2 field1 fieldn

2、FROM table_name實現(xiàn)數(shù)學四則運算數(shù)據(jù)查詢SELECT 1+1Select filed1*2設置顯示格式數(shù)據(jù)查詢SELECT CONCAT(ename,雇員的年薪為：,sal*12) yearsalary FROM t_employee;帶有關(guān)系運算符和邏輯運算符的條件數(shù)據(jù)查詢。Select col from table_name where a=b and c1 or d12帶BETWEEN AND關(guān)鍵字的條件數(shù)據(jù)查詢。SELECT field1 field2 fieldn FROM table_name WHERE field BETWEEN VALUE1 AND VALUE2

3、帶IS NULL關(guān)鍵字的條件數(shù)據(jù)查詢。SELECT field1 field2 fieldn FROM table_name WHERE field IS NULL;帶IN關(guān)鍵字的條件數(shù)據(jù)查詢。SELECT field1 field2 fieldn FROM table_name WHERE field IN (value1,value2,value3,valuen);帶LIKE關(guān)鍵字的條件數(shù)據(jù)查詢“_”通配符，該通配符值能匹配單個字符?！?”通配符，該通配符值可以匹配任意長度的字符串，即可以是0個字符，1個字符，也可以很多個字符。Show variables like %gen%;SELEC

4、T field1 field2 fieldn FROM table_name WHERE field LIKE value;SELECT field1 field2 fieldn FROM table_name WHERE CONDITION ORDER BY fileldm1 ASC|DESC,fileldm2 ASC|DESC,SELECT field1 field2 fieldn FROM table_name WHERE CONDITION LIMIT OFFSET_START,ROW_COUNTCOUNT()函數(shù)：該統(tǒng)計函數(shù)實現(xiàn)統(tǒng)計表中記錄的條數(shù)。AVG()函數(shù)：該統(tǒng)計函數(shù)實現(xiàn)計算字

5、段值的平均值。SUM()函數(shù)：該統(tǒng)計函數(shù)實現(xiàn)計算字段值的總和。MAX()函數(shù)：該統(tǒng)計函數(shù)實現(xiàn)查詢字段值的最大值。MIN()函數(shù)：該統(tǒng)計函數(shù)實現(xiàn)查詢字段值的最小值。SELECT function() FROM table_name WHERE CONDITION GROUP BY field;SELECT GROUP_CONCAT(field) FROM table_name WHERE CONDITION GROUP BY field;SELECT GROUP_CONCAT(field),function(field) FROM table_name WHERE CONDITION GROUP BY field1,field2,fileldn;SELECT function(field)