3 v^@shdZddlmZmZGdddeZGdddeZGdddeZGd d d eZGd d d eZd S)z;Database functions that do comparisons or type conversions.)FuncValuecsPeZdZdZdZdZfddZfddZfdd Zd d Z d d Z Z S)Castz)Coerce an expression to a new field type.ZCASTz,%(function)s(%(expressions)s AS %(db_type)s)cstj||ddS)N) output_field)super__init__)self expressionr) __class__I/usr/lib/python3.6/site-packages/django/db/models/functions/comparison.pyr sz Cast.__init__c s"|jj||d<tj||f|S)Ndb_type)r cast_db_typeras_sql)rcompiler connection extra_context)r r r r sz Cast.as_sqlc  s|jj|}|d krZd}tj||fd|i|\}}|dkrBdnd}|jd|||fS|dkrd }tj||fd|i|S|j||f|S) Ndatetimetimezstrftime(%%s, %(expressions)s)templatez%H:%M:%fz%Y-%m-%d %H:%M:%frdatezdate(%(expressions)s)>rr)rr rrinsert) rrrrr rsqlparams format_string)r r r as_sqlites  zCast.as_sqlitecKs.|jjdkrdnd}|j||fd|i|S)N FloatFieldz(%(expressions)s + 0.0)r)rget_internal_typer)rrrrrr r r as_mysqlsz Cast.as_mysqlcKs|j||fddi|S)Nrz(%(expressions)s)::%(db_type)s)r)rrrrr r r as_postgresql$szCast.as_postgresql) __name__ __module__ __qualname____doc__functionrrrrrr __classcell__r r )r r rs   rcs0eZdZdZdZfddZfddZZS)Coalescez:Return, from left to right, the first non-null expression.ZCOALESCEcs&t|dkrtdtj||dS)Nz+Coalesce must take at least two expressions)len ValueErrorrr)r expressionsextra)r r r r/s zCoalesce.__init__c sT|jjdkrD|j}|jdd|jDtt|j||f|S|j||f|S)N TextFieldcSsg|]}t|ddqS)ZTO_NCLOB)r$)r).0r r r r :sz&Coalesce.as_oracle..)rrcopyset_source_expressionsget_source_expressionsrr&r)rrrrclone)r r r as_oracle4s zCoalesce.as_oracle)r r!r"r#r$rr3r%r r )r r r&+s r&cs0eZdZdZdZfddZfddZZS)Greatestz Return the maximum expression. If any expression is null the return value is database-specific: On PostgreSQL, the maximum not-null expression is returned. On MySQL, Oracle, and SQLite, if any expression is null, null is returned. ZGREATESTcs&t|dkrtdtj||dS)Nr'z+Greatest must take at least two expressions)r(r)rr)rr*r+)r r r rJs zGreatest.__init__c stj||fddi|S)zUse the MAX function on SQLite.r$MAX)rr)rrrr)r r r rOszGreatest.as_sqlite)r r!r"r#r$rrr%r r )r r r4@s r4cs0eZdZdZdZfddZfddZZS)Leastz Return the minimum expression. If any expression is null the return value is database-specific: On PostgreSQL, return the minimum not-null expression. On MySQL, Oracle, and SQLite, if any expression is null, return null. ZLEASTcs&t|dkrtdtj||dS)Nr'z(Least must take at least two expressions)r(r)rr)rr*r+)r r r r^s zLeast.__init__c stj||fddi|S)zUse the MIN function on SQLite.r$MIN)rr)rrrr)r r r rcszLeast.as_sqlite)r r!r"r#r$rrr%r r )r r r6Ts r6cs$eZdZdZdZfddZZS)NullIfZNULLIFr'c s:|jd}t|tr(|jdkr(tdtj||f|S)Nrz2Oracle does not allow Value(None) for expression1.)r1 isinstancervaluer)rr)rrrrZ expression1)r r r r3ls zNullIf.as_oracle)r r!r"r$arityr3r%r r )r r r8hsr8N) r#django.db.models.expressionsrrrr&r4r6r8r r r r s &