WHEN condition THEN result1 ELSE result2 END 1. 2. 3. 解释一下,语句中的condition是条件判断,如果该判断结果为true,那么CASE语句将返回result,否则返回result2,如果没有ELSE,则返回null。CASE与END之间可以有多个WHEN…THEN…ELSE语句。END表示CASE语句结束。 场景:score 大于等于90为优秀,80-90为良好,60-80...
如果参数X为null,或者不能无损转换为数字,则sign(X)返回null。 示例 数据 Price 12.3 -3.5 0 查询语句 select Price, sign(Price) AS "函数值", case sign(Price) when 1 then '正数' when -1 then '负数' else '零' end AS "正负数" from tCeShi 返回结果 soundex(X) 返回字符串X的 soundex 编...
while( SQLITE_ROW==sqlite3_step(pStmt) ){ /* Do something with the row of available data */ } /* Finalize the statement. If an SQLITE_SCHEMA error has ** occured, then the above call to sqlite3_step() will have ** returned SQLITE_ERROR. sqlite3_finalize() will return ** SQLITE_...
insert or replace into table_name( id,type) values (1,0); 方法二: 代码语言:javascript 复制 insert or ignore into table_name (id,type) values (2,0); 方法三: 代码语言:javascript 复制 IF NOT EXISTS(SELECT * FROM table_name WHERE….) THEN INSERT INTO ... ELSE UPDATE SET ... 6.sq...
synchronous=FULL.If durability is not a concern, then synchronous=NORMAL is normally all one needs in WAL mode.在WAL模式下,当同步为NORMAL (1)时,WAL文件在每个检查点之前同步,数据库文件在每个完成的检查点之后同步,当一个检查点后WAL文件开始被重用时,WAL文件头同步,但在大多数事务期间不发生同步操作。
expr ISNULL | expr NOTNULL | expr [NOT ] BETWEEN expr AND expr | expr [NOT ](value-list) | expr [NOT ](select-statement) | expr [NOT ] IN [database-name. ]table-name | [EXISTS ](select-statement) | CASE [expr ] ( WHEN expr THEN expr )+ [ELSE expr ] END | CAST (expr...
int locked = 0; /* True if some process holds a RESERVED lock */ /* Race condition here: Another process might have been holding the ** the RESERVED lock and have a journal open at the sqlite3OsAccess() ** call above, but then delete the journal and drop the lock before ...
in its test expressionsselect a, case when b<>0 then 1 else 0 end from t1;select a+10, case when not b<>0 then 1 else 0 end from t1;select a+20, case when b<>0 and c<>0 then 1 else 0 end from t1;select a+30, case when not (b<>0 and c<>0) then 1 else 0 end...
if (argc == 2) { zEditor = (const char*)sqlite3_value_text(argv[1]); } else { zEditor = getenv("VISUAL"); } if (zEditor == 0) { sqlite3_result_error(context, "no editor for edit()", -1); return; } if (sqlite3_value_type(argv[0]) == SQLITE_NULL) { ...
NULL空值。INTEGER值是一个带符号的整数，根据值的大小存储在1、2、3、4、6或8字节中。REAL浮点数字...